From the Bureau of Justice Statistics:
Over 118 million applications for firearm transfers or permits were subject to background checks from the inception of the Brady Handgun Violence Prevention Act of 1993 on March 1, 1994, through December 31, 2010. During this time period, about 2.1 million applications, or 1.8%, were denied. In 2010, 1.5% 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). The denial rate for applications checked by the FBI (1.2%) was lower than the rate for checks by
state and local agencies.