We didn't see any reference to the fact that NL teams have a 23-16 lead in Game Seven--there has been much more attention paid to the ongoing "games won on the road" phenomenon that's still in play after the Nationals' 7-2 win in Houston last night. [NOTE: The table has been updated as of 11/1 to reflect the 2019 outcome: the NL now leads in Game 7 wins, 24-16. We still haven't seen any mention of it anywhere else...]
This table shows us that the greatest number of Game Sevens in any decade occurred in the 1960s, with the adjacent decades (50s, 70s) clustering up with five more apiece. 2019 brings our current decade into a tie with the 50s and 70s.
One feature of this chis a breakout by the "suffix" of a year--all years ending in 0, 1, 2, etc. The AL has fared extremely well in years ending in "2," winning five of six Game Sevens. Which means that in all other years, the NL has put up a 2-to-1 advantage in these games (22-11). The NL team has won the only two Game Sevens to occur in a year ending in "9."
An occult little table, but hopefully one with some amount of interest...
As you'd expect, the Yankees have been in the most Game Sevens (a total of 11), but they are not the most successful team in such a situation, winning only five times (the last in 1962).
The Cardinals are the most successful team in Game Seven situations, winning seven times out of ten appearances in a "do or die" game.
By far the most successful franchise when we measure by winning percentage, however: the Pittsburgh Pirates, who've won all five of the Game Sevens in which they've appeared.
Two notes: 1) we've obviously left the color-coding blank for the 2019 series; 2) we've shown the Nationals as their own franchise, since their lineage is from the Montreal Expos; the other Washington appearances (from 1924 and 1925) have been put into the Minnesota data. (The same principle is applied to all franchises who've moved around; this should be self-explanatory). [NOTE: As of November 1, the color-coding has been updated to reflect the 2019 outcome.]
Enjoy these visual aids, and enjoy Game Seven