At first,

Natural numbers from 2 to 12 are as follows:

2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12

Now,

Prime numbers among them are:

2, 3, 5, 7, 11

Hence,

There are total 5 prime numbers out of 11 natural numbers.

Therefore,

The required fraction is