My question is how do you know what % your dog is of East or West or Czech or whatever?

I see advertisements with 90% East/DDR & 10% Czech....Is there a list somewhere of what the major bred dogs are??

Well, it's based off of overall genetic percentages. Consider one puppy/dog:
Each parent contributes 50% of the genetic make-up of that puppy/dog-easily understandable.
Each grandparent contributes  25% genetics of the puppy/dog-again, simple break-down.
Each great-grandparent 12.5% of the puppy/dog-just half of 25% from the previous grandparent generation...
Each great-great grandparent contributes 6.25%,
Each great-great-great grandparent contributes 3.125%, and so forth.
Just remember, adding up the percentages properly has to equal 100% for the puppy/dog for it to be even potentially right.{2 parents(2x50%=100%), 4 grandparents(4x25%=100%), 8 great-grandparents(8x12.5%=100%), 16 great-great grandparents(16x6.25%=100%) and so forth}
And now obviously- a great-great grandparent isn't going to be as influential on a puppy genetically as a grandparent. We have done established that a great-great grandparent only contributes 6.25% genetics for a pup whereas a grandparent contributes 25%. Its obvious who contributes more.
So, if a dog advertized has one Czech bloodline grandparent and the rest are WGR working lines grandparents, then that dog would be said to be 75%(3 out of 4)  WGR working lines and 25% Czech(because  only 1 out of 4 grandparents was Czech). 

If the combination of bloodlines was more complicated(meaning, other different bloodlines used), then you would look at it the exact same way and assign each ancestor a percentage value  based on where it is at in the pedigree and you can use color-coding for simplification (assign green for WGR show, blue for WGR working, red for Czech, orange for DDR to make it EASY for yourself to follow)-and the end figure HAS to equal up to 100% or else it's not done right.  And yes, it does include having a nice knowledge of what bloodline is what-without that information your knowledge is going to be limited. And, genetics aren't exactly cut and dried perfect, either-this is just giving a basic understanding of what percentages mean what-some dogs tend to be stronger in their genetics for certain things than othersand 2ndary genetic effects can happen and so forth, so it either may or may not come out. That's why some pups come out MARKED LIKE or ACT like a grandparent, not either parent, per say. It's why I always say, "breeding animals is not and never will be a perfected science."  :o) Hope that helps.

 How is there accent?

Like this: (by the way, I'm not 100% sure you could get as close as a 90/10 unless you average percentages). This is an example only. I'm using names I know, but not pedigrees, per say. I'm trying to keep this simple, yet complicate it so you can SEE how it works. The dog in percentage question is JADA-what is her percentage break-down on understanding her bloodlines? We wanna figure out, by the pedigree I'm giving her, what percentage of what she is. Ok.
 

                                                                G G-Sire: Tim (100% Czech) 
                                    G-Sire: Titus (Czech/Working)
                                                                G-G Dam: Mindi (100% WGR working)
             Sire: Kohle (Czech/WGR.working/DDR combo)
                                                                 G-G-Sire: Tino(100% DDR)
                                     G-Dam:  Meika (WGR working/DDR combo)
                                                                  G-G-Dam: Kora (100% WGR working)

Jada(?)

                                                    G G-Sire: Marko (100% WGR show)
                                   G-Sire: Panjo (WGR SHOW/DDR)
                                                    G-G-Dam:

I'll restart with Jada's mom's side...
                                          G G-Sire: Marko(100% WGR show)
                               G-Sire: Panjo(WGR Show/DDR)
                                          G-G-Dam: Jetta (100% DDR)
        Dam: Meika (WGR Show/DDR/Czech combo)
                                            G-G-Sire: Ronne (100% Czech)
                              G-Dam: Quina (Czech/WGR working)
                                            G-G-Dam:  Hera (WGR working)

This is a typical 4-gen pedigree. We need to work from the furthest ancestor information we have in order to accurately figure out what Jada's bloodline percentages are. Great-grandparents contribute 12.5% of a dog's percentage.
So, 3 great-grandparents are WGR working(Mindi, Kora & Hera), so 12.5%x3=37.5% of Jada is WGR working lines.
2 great grandparents(Tino & Jetta) are DDR, so 12.5%x2=25% of Jada is DDR.
2 great grandparents(Tim & Ronne) are Czech, so 12.5%x2=25% of Jada is Czech
and 1 great-grandparent(Marko) is WGR show, so 12.5%x1=12.5% of Jada is WGR show.
Based from this information, we could accurately advertise that Jada is 37.5%WGR Working/25%DDR/25%Czech/12.5%WGRShow lines.
Or to put it in more general terms, Jada is 87.5% working and 12.5% show lines.
If one wanted to make these averages a little simpler to understand, one could say Jada is 90% working/10% show lines and STILL be pretty accurate overall in the information provided. Hope that helps.

Hmmm, took me a few hours, but spent the time and finally came out to a round about percentage of 80% West and 20% East for my male. I had to go way back into the generations, but it is easy so long as you do it as already mentioned. Just takes time.

My female is considered full Czech, however, she has DDR back in the older generations because Czech lines were created using DDR lines. Someone correct me if I am wrong.

DDR(East German): http://www.pedigreedatabase.com/gsd/pedigree/364679.html.  Flori vom Kameruner Eck is not full ddr, Gebrüder Grimm has west german lines

katjo74   DDR: Grafental, Schaferleisel, Rolandsteich, Haus Himpel, Marderpfahl, zwie Steinen, Rundeck.

Grafental is the only one left and they breed more west show then east german dogs 

Really, SDG? I was told they (Grafental) were popular for DDR lines. I know a stud  named Treu who's full brother is a Grafental  Stud Dog(or he at least WAS one of theirs)-True's sire's side is Grafental dogs. They may have moved him on by now.
K9SAR-I'll look at your links here in a minute.

Marko vom Cellerland is the foundation of  some of the strongest West workinglines.(Like the Maineche lines), I would certainly not classify him as a showline dog in the sense of Canto/Quanto. Name me some current showlines that use Marko as a foundation???

Canto was never VA as a dog, because of his mother Zilly. It appeared that when you mentioned Marko it was in the context of a showdog as you identified Canto/Quanto. The only similarity between Marko and Canto is that they were both shown in the showring. I understand your intent.....just don't like seeing Marko associated with showlines as people know them today.