Excel Chart help

[Kasturi]

I am creating a chart with data that covers for the past 6 months. Some of the months contain no data. For example I am tracking audits. Some months an audit wasn’t done for this person. I have written a formula =IF(A2="",NA(),A2) to show #N/A if there were no audits done for that month. So for example if January had no audits it would come back as #N/A and if Feb had an audit it would show the results of that month.

My chart is showing the #N/A, but I would like for it to just show NA without the #/. Is there a way (formula, conditional format, etc) that will allow me to do this?
I had it showing 0% instead of the #N/A, but this can lead to some confusion if in fact this person did receive a 0% error rate as opposed to no audit at all.

I also tried using the "NA" instead of the NA(), but this places the value on the chart as 0%.

Not sure if this made any sense at all. It was much clearer in my head.