Running total not working for one column?

Hello,

I'm trying to compare the running total of two counts, basically when an agreement became effective and then terminated. When I do this, the effective dates work exactly as expected. I run quick measure -> running total -> base value = count of agreement -> Field = effective date (year). However, when I try the same with terminated dates, the graph is completely wonky. 

The only thing I can figure that is different between the two is that the "terminated agreements" column has a bunch of empty cells (agreements have not been terminated yet). Any ideas?

Thanks, I'd really appreciate any help!