Would you want there to be a zero for those months that have no activity? If that's the case you could create a calculation similar to the following:
Then, find your monthly average based on this calc.
Hope this helps!
Thanks Tracy, but that doesn't quite get me there. The red reference lines below indicate the average number of proposals that are closed each month. For FY14, that number ought to be 1.75 (as the filter in place stops at Oct. 31 2013) instead of 2.3. However, because there is zero activity in July, it does not count that month, The same is true for October in FY13. The average should be 2.6 and not 2.8. It is only calculating the average based on 11 months of activity. I'm surprised there isn't a clearer work around for this, as I would think this isn't a particularly novel visualization to create.
There probably is a work around. If you can post your workbook, or a sample .twbx file that demonstrates the issue, someone will find you a solution.
Are you sure adding a 0 value for those months that are not being counted will not resolve this? In your screenshot, it does not appear that you have put that into place yet.