The test results for the Trident while in development were equally impressive, with 87 percent successful (in 23 development tests) for the Trident I and 98 percent (49 tests) of the Trident II. The Trident I served from 1979-2005, while the Trident II entered service in 1990.
This success is in sharp contrast to the problems Russia and China have had developing SLBMs. The latest Russian SLBM, the Bulava (also known as R-30 3M30 and SS-NX-30), was almost cancelled because test flights kept failing. The Bulava finally successfully completed its test program on December 23rd, 2011. That made 11 successful Bulava test firings out of 18 attempts. The last two missiles make five in a row that were successfully fired. As a result of this, the Bulava has been accepted into service, with a development test firing success rate of 61 percent.
Then there is the Chinese JL (Julang) 2 SLBM, which was supposed to enter service five years ago and still hasn’t. This missile has had a lot of problems, as have the SSBNs that carried them. The 42 ton JL-2 has a range of 8,000 kilometers and would enable China to aim missiles at any target in the United States from a 094 class SSBN cruising off Hawaii or Alaska. Each 094 boat can carry twelve of these missiles, which are naval versions of the existing land based 42 ton DF-31 ICBM. No Chinese SSBN has ever gone on a combat cruise because these boats have been very unreliable and they have no dependable SLBMs to carry.