Count particular subforms

I wrote a script to count the total number of subforms the user dynamically creates. I used the following script that works correctly:

var count = _Subform2.count;

But now I need to count only the Subforms that the user did not select "N/A" from a dropdown object (Score) located here:

Subform2.Table1.Row2.Score

The dropdown has the following list 0, 1, 2, 3, 4, and N/A. How do I count only the dynamically created subforms that do not have "N/A" selected in the Score dropdown object?