Calculate count of degree

[#1]

Hello Everybody

How can i calculate count of degree for A,B,C?

Degree expression =>  if([Exclusive Percentage]<=.8,'A',if([Exclusive Percentage]<=.9,'B','C'))

Store	Sales	Accumulated Sales	Inclusive Percentage	Exclusive Percentage	Degree
1703	22,030,000	22,030,000	2.096%	0.000%	A
708	21,821,000	43,851,000	4.172%	2.096%	A
706	19,766,000	63,617,000	6.053%	4.172%	A
1912	14,876,000	78,493,000	7.468%	6.053%	A
1610	4,045,000	837,245,000	79.661%	79.276%	A
1510	4,005,000	841,250,000	80.042%	79.661%	A
1568	3,944,000	845,194,000	80.417%	80.042%	B
1220	3,920,000	849,114,000	80.790%	80.417%	B
1906	3,902,000	853,016,000	81.161%	80.790%	B
1561	3,747,000	856,763,000	81.518%	81.161%	B
1218	2,730,000	949,728,000	90.363%	90.103%	C
1402	2,695,000	952,423,000	90.619%	90.363%	C
1709	2,690,000	955,113,000	90.875%	90.619%	C
1934	2,682,000	957,795,000	91.130%	90.875%	C
1567	2,665,000	960,460,000	91.384%	91.130%	C

[#2]

Thanks.