qChart data line skips when values are blank

I have a qChart line graph which just shows a count of "things" every month. Sometimes we forget to collect the data for the month so do not enter data for that month. qChart will then stop displaying a line from the last available point to the next available point.

For example, I have data for January, February, skip March, April, and May. qChart will generate a line connecting January and February then nothing else. I want the line to go from January, to February, to April, to May.

How can I tell qChart to continue the line? See attached sample.