How to get the total number of line code in Git repository?

Hello,

I am working to get the Github metrics. One of the metrics we want to get is how many line of code changed within a date range. Looking at the online doc: http://www.visualstudio.com/integrate/reference/reference-vso-git-overview-vsi, I didn't find any REST Api can do this. I was wondering is there a workaround?

Thanks,

Zhixing