Since the NFL adopted rules changes in 1994 aimed at increasing scoring, there has been a steady uptick in offensive production, to the point where scoring is now at a record pace. Among the rules changes instituted nearly 20 years ago were the introduction of the two-point conversion, kickoffs being moved back from the 35 to the 30 (they have since been put back to the 35 as a result of an increase in injuries on returns) and missed field goals result in the defensive team taking possession at the spot of the kick instead of the line of scrimmage.
The year before the rules changes were adopted, games averaged just 37.4 points per game. Through 15 weeks so far this season, games are averaging 47.5 points per game. If that number holds, it will be the highest total in NFL history.