The official answer is 2 are deployed at any one time and 3 others can be made ready within thirty days. That's been the 2+3 deployment plan for the last 20 years, so I've read. I've also seen the 8 of 11 deployable number but that doesn't seem supported by most defense experts.
The real answer to how many are deployable at this time is a controversial topic. Because of postponed maintenance, extended deployments, prolonged shipyard stays and difficulty of getting the new Ford Class carriers operational we may not meet the 2+3 standard we once had. May be a crisis in the making.
All of my favorite creatures have white bottoms.