How Big is Your Word-Hoard?

Today's Daily Writing Tip talks about Test Your Vocab, which asks you some questions and then estimates how many words of English you know. The sentence in the description that really struck me was this:

Adult vocabulary size appears to be principally determined by reading habits between ages 4 and 15.

I took the Test Your Vocab quiz, but I can't say how I did because "it’s considered bad form to reveal your score or to ask others how they scored."

P.S. "Word-Hoard" is an Old English term for the words you know: "Words are useful to have, and to cherish as one of The Good People gloats over his gold under the hill."

P.P.S. If you're over 15 & want to expand your vocabulary, don't give up!
12 Ways to Learn Vocabulary with the New York Times
Wiki-How To Build Your Vocabulary