Results show that since the inception of the Brady Act, over 118 million applications for firearm transfers or permits were subject to background checks. About 2.1 million applications, or 1.8 percent, were denied; 1.5 percent of the 10.4 million applications for firearm transfers or permits were denied by the FBI (approximately 73,000) or by State and local agencies (approximately 80,000); among the 21 State agencies that reported reasons for denial, a felony conviction or indictment was the most common reason to deny an application in 2010 (31 percent); and a State law prohibition (16 percent) was the second most common reason (excluding other prohibitions). Included are estimates of applications and denials conducted by each type of approval system from 1999 to 2010. Also provided are data on reasons for denial, appeals of denied applications, arrests for falsified applications and outstanding warrants, and counts of records in the National Instant Criminal Background Check System (NICS) Index of persons prohibited under federal law from receiving or possessing a firearm. Data for this study were collected from surveys of State and local agencies who collected information on firearm background check activity and combined this information with FBI NICS transaction data.