The Mets opened Citi Field on April 13, 2009. For the first three seasons, the spacious stadium proved to be a pitcher's park. Citi Field averaged 1.432 home runs a game from 2009-11, the lowest number in the major leagues. During the 2011 offseason, the Mets decided to lower the left field wall from 16 to eight feet; bring right-centerfield in from 415 feet to 398 feet; and left-center from 371 feet to 358 feet.
This database tracks every home run hit at Citi Field before and after the outfield walls were adjusted.