The taxicabs of the United States make up a mature system; most U.S. cities have a licensing scheme which restricts the number of taxicabs allowed. As of 2012, in the United States: the total number of taxi cab drivers is 233,900; the average annual salary of a taxi cab driver is $22,820; the expected percent job increase over the next 10 years is 16%. Some cities use "taxi medallions" as permits for taxicab drivers to pick up passengers. The medallions have generally been considered a great investment, but real-time ridesharing companies have been eroding their value.