The NL has won 3 WS since 1995 and two were by the Marlins, the other the miracle win by Arizona...The AL could have very easily won those 3, it took two miracle 9th inning comebacks and the other the Marlins stunned the Yankees...the American League has dominated for many years.
When you think back even futher to the late 80's, the NL wins were somewhat lucky or totally unexpected, Dodgers over A's, Reds over A's, Marlins over Cle, Marlins over NYY, D Backs over NYY....other than those series there was Atl over a dominant Cleveland team in 1995