Serbian Americans (Serbian: Амерички Срби/Američki Srbi ) are United States citizens of Serb ethnic ancestry. As of 2012, there are 199,080 American citizens of "Serbian ancestry" who identify as having Serb ancestry. However, the number may be higher, as some 328,547 people who identify as Yugoslavs living in the United States, and many Yugoslav immigrants were of Serb ethnicity.
The number may be higher because many African Americans are of Serb ethnicity. 
Many African Americans are from Africa and black, while Serbian Americans are white and from Europe - therefore, my statement is definitely incorrect; although there may be some mixed African Americans with some Serbian genes, a reasonable, common sense guess would not include the word "many". I think the system struggled because it doesn't understand basic racial differences.
( z1 possible :ARG1 ( z2 have-degree :ARG1 ( z3 number ) :ARG2 ( z4 high :ARG1 z3 ) :ARG3 ( z5 more ) ) :ARG1-of ( z6 cause :ARG0 ( z7 ethnicity :mod ( z8 ethnic-group :name ( z9 name :op "Serb" ) ) :domain ( z10 person :mod ( z11 continent :name ( z12 name :op "Africa" ) ) :mod ( z13 country :name ( z14 name :op "America" ) ) :quant ( z15 many ) ) ) ) )