States decided by a majority vs. states decided by a plurality

[DPKdebator]

Also only one state in 2012 was carried by plurality: Florida.

In 2008, Montana, Missouri, Indiana, and North Carolina were decided by pluralities.

In 2004, Wisconsin, New Mexico, and Iowa were decided by pluralities.

In 2000, Oregon (this seems really weird in 2017, huh?), New Mexico, Minnesota, Iowa, Wisconsin, Florida, New Hampshire, and Maine were decided by pluralities.

[DPKdebator]

Also only one state in 2012 was carried by plurality: Florida.

In 2008, Montana, Missouri, Indiana, and North Carolina were decided by pluralities.

In 2004, Wisconsin, New Mexico, and Iowa were decided by pluralities.

In 2000, Oregon (this seems really weird in 2017, huh?), New Mexico, Minnesota, Iowa, Wisconsin, Florida, New Hampshire, and Maine were decided by pluralities.

It appears as though elections without an incumbent running have far more plurality victories (2000, 2008, 2016) than those with an incumbent running (2004, 2012).

Well, 2000 and 2016 had relatively strong third-party showings (which 100% contributes to plurality votes); a possible reason for this is that during incumbency elections, people registered with parties stick with their party's candidate and don't want to "waste their vote," while less people feel this way in open elections.