I want to calculate the percentage for when "b" apears in M2:M10 and the
number is between 50 and 100
=SUMPRODUCT(--(B2:L1050),--(B2:L10<=100)/COUNT(B2:L10))

a1 b2 c2 m2
111 b
99 s
200 s
110 b
55 b
99 s
225 b
b % = 25% (50 and <=100 b2:l10)

Thank you in advance.