In the Star Trek TNG episode "The Royale", the away team find the remains of an astronaut, his uniform had an American flag with 52 stars

On the sleeve is a version of the United States flag with 52 stars

Digging a bit further, the Memory Alpha page about the USA, states that in the year 2033, in regards to this:

The US added a 52nd star to its flag, indicating the inclusion of a 52nd state to the union. The flag had 52 stars until 2079

What states do the extra 2 stars represent?

Also, why did this number change in 2079?