The NICS didn't actually go into effect until '98 and thefts of firearms from the home had already been in steady decline since '94 and through 2010. Make what you will of it but it looks either inconclusive or ineffective. But it sure makes NICS checks look good if you forget that they didn't go into effect in '93 with the passing of the Brady bill.
Yes on NICS, not actually on background checks.
Background checks went into effect in most states in 1994. Many sherriffs and other law officials filed lawsuits on tenth ammendment grounds due to the unfair burden and cost that the Brady Bill imposed upon them. This was overturned in the court conviently about the same time NICS came on line in Printz v. United States