Reading a lot of books and watching/listening to a lot of media put me quite high: CFR C2, 19 200 word families, above 78% of native speakers, above 99.9% of non-native speakers.

However. In real life I use maybe 1% of that :D Especially in in iternational settings where you eventually end up speaking a common denominator (not necessarily lowest common denominator).

I do get by writing on HN and reading books though :)