The most useful 2-letter word for Scrabble hooks

You're looking for a hook on the Scrabble board and there are a few 2-letter words on the board that you can add to. Here they are:

IT

EN

AR

AT

YE

Assuming that you're unhindered on both sides of the word, which of these can yield more hooks than any other two-letter word in Scrabble?

Total hooks for each word (including letters added before and after the word) are as follows:

IT = 15

EN = 15

AR = 22 -- the champ!

AT = 19 (this has the most possible hooks -- 17 -- BEFORE the word)

YE = 16

AR hooks BEFORE the word include: bcefgjlmoptvwy

AR hooks AFTER the word include: bcefkmst