Number of Months between two dates

[trevb]

This seems like a really dumb thing to be asking.

I need to count the number of Months between two dates.  I can happily find out the number of days, but that doesn't help much as number of days in a month varies.  This can easily be done in Excel using DateDiff but I cannot figure out how to do this in PowerQuery.  I need that figure to move to the next step of my query.

The only other thing that might do this is if I could get a count of a group of rows.    

I'd enjoy figuring t this out for myself if I had the time but I need to get this done quickly so any hints gratefully received.