I have tried the below mentioned formula to calculate the % of updates from past 2 months. Updated the month value (in numbers) in column 'J'. For a few of the entries no updates required and have marked them as NA. While calculating the percentage, I am excluding NA values and count the number of updated entries in past 2 months. I am using the below mentioned formula :
=(COUNTIF(J4:J345,">(INT(MONTH(TODAY())-2))"))/(COUNTIF(J4:J345,"<>"&"NA"))
If I replace (INT(MONTH(TODAY())-2)) with the number 3, the result is correct. However, if I try to make it a generic one with the formula, it does not provide the correct value and instead, gives me the count of "NA" in that column.