I'm looking for stats that differentiate between free throws that come off a missed shot and those that come after a made shot (and-one play). Any ideas?

For example, box scores show free throws as attempted and made (E.g. 8-10). But they don't say if they were off 5 missed field goals, or 4 missed field goals and 2 3-point plays/and-ones. I don't know how to get this info short of observing entire games, which is beyond the scope of my research capabilities.

I'm trying to put together an overall offensive efficency stat. Geeky stuff, I know. Any help is appreciated.