Aproximatley what percent of strikeout leaders had 175 or more strikeouts during these years?

2000-187 1994-128
1999-171 1993-169
1998-171 1992-154
1997-175 1991-175
1996-160
1995-150

I don't understand how to find a percent.

If I interpret your data correctly,

the number represents the number of strikeouts of the top player for that year.
if so, then just count the number of years, which is 10
then the number of years with 175 or more, which is 3

so percentage is 3/10 = .3 = 30%