exclude data that meet certain criteria

Hello - I am trying to show the average of 5 columns in a table. The value options are 1 (for yes) 0 (for no) and NA (for na).

The problem I am running into is that I gradually enter data over time and if I have a column that only consist of the answer na I get a false 0% average. I cannot use an IF statement to exclude 0 because that could be a correct average if the answer is 0 (or no) and not NA.

One possible solution is to tell excel not to include any cells that have the #Div/0! error in the final calculation. Is there a way to do this?

=IF(COUNT(A1:E1) = 0, "NA", AVERAGE(A1:E1) )