In all playoff games, the AL teams averaged 4.87 runs per game. The AL runs per game this year was 4.46 during the regular season.
The NL average so far is 4.63 (not counting tonight's game with the Cards leading 11-6 in the bottom of the 7th). If it ends up with that score, the NL average will be 4.88. If the Brewers could win 12-11 and tomorrow's game ends up 1-0, the NL average will be 4.82. The NL runs per game this year was 4.13 during the regular season.
Only 10 of the 30 games so far had both teams scoring 4 or fewer runs. Only 5 games had both teams scoring 3 or fewer runs.