While there is a lot of unease about ballistic missile development in North Korea and Iran, the number of ballistic missiles in service has dropped drastically since the end of the Cold War (the late 1980s). Since then, the number of ICBMs in service has been reduced by half (from about 4,000 to about 2,000.) IRBMs (with a range of 3,000-5,000 kilometers), have declined over 95 percent. There are only twenty such systems in service (with China and India) today.
MRBMs (medium range ballistic missiles, with a range of 1-3,000 kilometers) in use have declined about a quarter. MRBMs have been the favorite with North Korea, China and Iran, because they are adequate for attacking neighbors. These days there are some 400 MRBMs in service.
SRBMs (short range ballistic missiles, with a range of under 1,000 kilometers) are one category where numbers may not have declined. It's uncertain how many are still in use, and that's because there are still so many Cold War era SCUD (and SCUD clones) around. Many of these missiles are rotting away in North Korean, Iranian and various other Middle Eastern warehouses. There are a lot of them sitting around in Russia, but not in usable form. Several nations are designing and building new SRBMs (especially North Korea, Iran, China). There are at least several thousand (more or less launchable) SRBMs out there. The best of them are not SCUDs, but more modern designs from China. There's a lot of work going on developing new missiles. Last year, there were nearly a hundred test launches, most of them for smaller missiles (like SRBMs and MRBMs).