People often say if you were to represent pi with letters, every book ever written would be contained therein.

We do not know if this is true or not. In order for this to be true, a number has to be "normal", meaning each number has the same density as every other number. And not just single digit number, but two digit numbers, three digit numbers, and so on. In other words, 11 must have the same density as every other 2 digit number.

It has never been proven that pi is normal, and so we do not know if the initial statement is true. There are conjectures that it is true, but this has yet to be definitively proven. It could be that after some arbitrarily large number, 11 stops occurring with the same density as other 2 digit numbers.