Let’s have more fun with the definition problem – you grew up in Williamsburg but never davened with kavanah, cheated a bit on waiting six hours, talked about politics during davening — then you ran away from home, went to college, wear a kippuh srugah and daven in a Young Israel – but you actually daven during davening, never discuss politics on Shabbos, and learn all day. Or vice versa? Which is OTD and which is a BT?
How about a Shomer Shabbos thief? What about a “conservadox” or “conservative” who totally gives up on kashruth and Shabbos (OTD or doesn’t count to start with). How about a totally assimilated Jew who adopts ingredient kashruth and stops working on Shabbos, but perhaps will turn on a light – but won’t go to his job.
A good frum sociologist might dream up an index to measure frumkeit for comparison purposes. It is interesting to note that frum institutions at all levels are growing, and non-frum ones are shrinking – but that may be due to birth rates more than anything else.