Time to complete work items

I want to try and find out how long it takes them to get an Idea into the market from a DevOps point of view.  This is as simple as tracking work item state transitions and when transitions were made. There are lots of different projects with different workflow states so something project specific would not be ideal.
 
I know JRS has access to these transitions times as I have seen a similar "average time in state" report before, but the current environment doesn't have JRS and an upgrade is not planned anytime soon. Insight is available so it may be possible to do something similar?

Would it be possible to make use of the RTC OSLC <g class="gr_ gr_185 gr-alert gr_spell gr_run_anim ContextualSpelling ins-del multiReplace" data-gr-id="185" id="185"> Api </g> to access the information somehow?
 
Any options would be useful