Pivot Table and Countif Function

ID B Month
A1 Pass Feb
A1 Pass Feb
A1 Pass Feb
A3 Fail Feb
A4 Fail Feb
A4 Pass Feb
A4 Fail Feb
A4 Pass Feb
A1 Pass Jan
A1 Fail Jan
A1 Pass Jan
A1 Pass Jan
A2 Fail Jan

I wonder if someone can help me solve the following problem:

I have excel datasheet with many records for example
I would like to sort out how many Pass/Fail I do have of each ID at
any month providing that the number of occurrences of the ID item is
more than a certain value per month, (in this case greater than 3) so
the pivotable will show the following results with the percentage for
each month:

Count of B
ID Month B Total Percentage
A1 Jan Fail 1 0.25
Pass 3 0.75
A4 Feb Fail 2 0.5
Pass 2 0.5
Grand Total 8

Instead of
Count of B
ID Month B Total Percentage
A1 Jan Fail 1 0.08
Pass 3 0.23
Feb Pass 3 0.23
A2 Jan Fail 1 0.08
A3 Feb Fail 1 0.08
A4 Feb Fail 2 0.15
Pass 2 0.15
Grand Total 13

Thank You
Amiram