In the early years of development, the field of biometrics suffered from high numbers of false accepts and rejects, underfunded company programs, and high per unit costs. While many companies have relied on card access, keypads, and proximity cards, there is evidence that attitudes toward biometrics are changing. For example, in 1991, sales of biometric devices more than doubled, excluding law enforcement fingerprinting business. While biometrics sales still account for only 5 percent of the ID market, its uses are becoming more mainstream. Although the government is the industry's primary customer, about 8,200 portals in the commercial sector are currently controlled by the five available types of biometric devices: retinal scan, fingerprint, hand geometry, signature, and voice. Reliability of biometric systems is measured by the numbers of false rejects and false accepts and by the system's throughput time.