I was having trouble with COUNTIF, so I fell upon this old thread:
http://www.mrexcel.com/forum/excel-questions/84490-countif-not-counting-all-values.html
In the third reply, fairwinds suggests using "=SUMPRODUCT(--(A1:A10={"y","n","n/a"}))" instead of COUNTIF.
For reasons I don't know, using...