reliance on the ease of memory search

Consider the letter K.
Is K more likely to appear as the first letter in a word OR as the third letter?

I have no idea! (Though I am fighting the temptation to google it...). My guess would be the third letter just because K's at the beginnings of words are relatively uncommon I think. But at the same time I can't think of a single word with K as the third letter. So... actually I have no clue. What's the answer!?