Benchmark Contest:Count character ratio in DNA file

RULES:
The program must count(without prior knowledge of file beyond its format) GC-content of source file.
GC-content is fraction of GC vs AT chars found in the file expressed as floating point number. http://en.wikipedia.org/wiki/GC-content
source file https://github.com/dubst3pp4/GC-Content-OOC/blob/master/Homo_sapiens.GRCh37.67.dna_rm.chromosome.Y.fa

>>8 Learn some math
60,363,186 bytes in file
1 thread 108,000,000 cycles =1.8 cycles per byte
2 threads 46,000,000 cycles =0.76 cycles per byte
And thats with PentiumG3220