Do Incumbent Presidents Who Increase Their Votes Always Win?

One claim going around is that for the past 150 years, no incumbent president has increased his raw vote total and lost (and this suggests voter fraud).

In the past 150 years, there were 38 presidential elections.  In 19 of those elections, there was no president running for reelection (an incumbent who was not elected cannot run for reelection).  Since the claim is only about incumbent presidents, we have to discard those.

That leaves 19 elections with an incumbent running for reelection.  Incumbent presidents won 12 times.  Since the claim is about incumbents who lost reelection, we have to discard these also.

In the past 150 years, only seven incumbent presidents have lost reelection in the general election.  (This does not count Gerald Ford, who was not elected initially.)  Presidents Taft, Hoover, Carter, and George HW Bush all lost in landslides.  The claim is only really relevant to incumbent presidents who lost narrowly, which includes Grover Cleveland, Benjamin Harrison and Trump.  A trend that only holds for three elections isn't much of a trend.

There is one more problem.  THE CLAIM IS FALSE.  Grover Cleveland got 4,914,482 votes in 1884, when he won, and 5,534,488 votes in 1888, when he lost.  Sadly, it seems that people don't bother to check claims like this before passing them on.