Below is a historical listing of the combat ships of the Navy. The count includes carriers, battleships, cruisers, destroyers, frigates, submarines, and amphibious ships. It does not include logistics support ships, mine warfare vessels, patrol craft, hospital ships, JHSV, and the like. I have also not included the LCS in the count since it currently has no combat capability. If/when it does, I'll include it.
Data is taken from http://www.history.navy.mil/branches/org9-4.htm
The trend is undeniable. The combat fleet is getting steadily smaller. Already, 13 ships have been announced for retirement next year although there are attempts underway in Congress to provide funding to retain 2-4 of those ships so the final number may vary. Even with a couple of scheduled commissionings, the net result will be a decrease of several ships for 2013.
While some may argue that today's ships are more capable than ever before, it's disturbing that combat power is being concentrated in ever fewer numbers which means the loss of any single ship is becoming ever more devastating. This phenomenon results in a situation where commanders are more and more reluctant to put ships in harm's way. We're already seeing this in the Navy's refusal to stand near a coastline due to the presence of shore launched anti-ship missiles which means that amphibious assaults must be conducted from well out to sea. I'll set aside the issue of whether that's ultimately a good thing or not and simply note that it's driven by fear of loss rather than tactical advantage.
The combat fleet is headed towards a level of 150 or so in the moderately near future (not withstanding the current administration's 30 year shipbuilding plan which is pure fantasy) given the budget limitations and the Navy's single-minded focus on building ever bigger and more expensive ships.
Compare the Navy's trend to China's and ponder the implications for yourself.
I'll update this from time to time.