President Donald Trump made thousands of false statements this year, averaging 15 a day, according to an analysis by The Washington Post.

At the beginning of the year, Trump had made 1,989 false statements. He had tripled his rate by the end of 2018, The Post reported.

His approach to facts may no longer be working. A poll by The Post found that fewer than three in 10 Americans believe many of his most common false statements.

President Donald Trump began 2018 by tweeting a thread of misleading statements and falsehoods about Hillary Clinton, Iran, and The New York Times. According to The Washington Post, those tweets were among the first of the president's approximately 5,600 lies, falsehoods, and mistruths of the year.

The Post's Fact Checker database, which tracks Trump's statements, calculated that the president averaged 15 falsehoods a day this year, nearly tripling his rate from last year. On the last day of the year, he has topped 7,600 false or misleading statements during his presidency, The Post found.

Trump's approach to facts might not be working for him anymore. A poll by The Post earlier this month found that fewer than three in 10 Americans believe the president's oft-parroted statements on issues like immigration, the border wall, and the Russia investigation.

Read more: Trump claims 'I always like to be truthful,' but his history of public statements before and after he became president prove otherwise

The Post's analysis found that Trump began 2018 with a similar pace of false statements as in 2017, accumulating 200 to 250 falsehoods a month. His output rocketed in June, when he reached 500 falsehoods, an escalation The Post attributed to the president going into "campaign mode."

The Post's Fact Checker blog, which measures the truth of statements made by politicians and other public figures with a "Pinocchio" scale, this year created a "Bottomless Pinocchios" measure for repeated false statements. So far, statements from Trump that have earned this distinction include falsehoods about the 2017 tax law providing the largest tax cut in US history and about the construction of a wall along the US-Mexico border.