President Donald Trump likes to boast that he and his achievements are the biggest and the best, and not just about the size of his nuclear launch button.

In recent weeks, Trump on Twitter and in speeches has repeatedly touted the rise of the stock market on his watch.

In a tweet on Jan. 5, 2018, Trump said, "Dow goes from 18,589 on November 9, 2016, to 25,075 today, for a new all-time Record. Jumped 1000 points in last 5 weeks, Record fastest 1000 point move in history. This is all about the Make America Great Again agenda! Jobs, Jobs, Jobs. Six trillion dollars in value created!"

And Trump has explicitly compared his stock market record with that of his predecessor, Barack Obama.

"The Fake News Media barely mentions the fact that the Stock Market just hit another New Record and that business in the U.S. is booming...but the people know! Can you imagine if ‘O’ was president and had these numbers - would be biggest story on earth! Dow now over 25,000," he tweeted on Jan. 4.

Dow goes from 18,589 on November 9, 2016, to 25,075 today, for a new all-time Record. Jumped 1000 points in last 5 weeks, Record fastest 1000 point move in history. This is all about the Make America Great Again agenda! Jobs, Jobs, Jobs. Six trillion dollars in value created! — Donald J. Trump (@realDonaldTrump) January 5, 2018

So how has the stock market’s performance under Trump measured up to that under his immediate predecessor?

Trump has solid evidence to point to when he brags about the stock market. But other presidents have seen rises, too, so it’s not unprecedented.

Numerically, Trump is on firm ground. Here’s a chart showing the Dow Jones Industrial Average since Trump’s election victory in November 2016. It shows that from the time Trump won the election until his Jan. 5 tweet, the Dow rose from 18,589.7 to 2,5075.1, or almost 35 percent.

That’s undoubtedly an impressive rise -- and it exceeded the Dow’s performance under Obama.

During the same period under Obama, the Dow rose from 9,139.3 to 10,572, or an increase of about 15.7 percent. Here’s the full chart:

That said, small changes in the timeline can produce big differences. The day-to-day volatility of the Dow means that presidential performance can vary dramatically depending on when you start and end your count.

For instance, Trump’s comparison falters if you look at the Dow’s performance between Inauguration Day and Jan. 5 of a president’s second calendar year in office, rather than Election Day.

Starting with Trump’s inauguration, the Dow has risen from 19,827.3 to 25,075.1 -- an increase of 26 percent. That’s impressive.

But it’s not as impressive as its performance during the equivalent period under Obama. Under Obama, the Dow increased from 7,949.1 to 10,572 — a rise of 33 percent.

In fact, the Dow’s rise was even more impressive under Obama if you start measuring at the market’s low point, on March 9, 2009, during the depths of the Great Recession. That day, the Dow closed at 6,547. Between then and Jan. 5 — a 10-month period — the Dow rose by a stunning 61 percent. That’s more than three times faster than Trump’s rise over the same period in his term.

It’s also worth noting that Trump is not alone among presidents in presiding over a bull market.

Most recent presidents have seen significant stock market increases over their terms. Presidents Obama, Bill Clinton and Ronald Reagan, for instance, all oversaw three-digit percentage increases over their eight year terms. The one president who lost ground was President George W. Bush, whose final year in office coincided with the onset of the Great Recession.

Here’s a summary:

President Length of term Closing Dow Jones Industrial Average Percentage increase in the Dow Jones Industrial Average Barack Obama 8 years 19,827 + 149 percent George W. Bush 8 years 7,949 - 25 percent Bill Clinton 8 years 10,578 + 227 percent George H.W. Bush 4 years 3,242 + 45 percent Ronald Reagan 8 years 2,235 + 135 percent

We’ll also note that it’s unclear how valuable the stock market is as a gauge of the country’s economic health. Not every American is invested, so it’s probably not the most important economic metric.

His administration’s pro-business policies on taxes and regulation may have been a factor in the growth, though experts also credit the current stock market rise to the strength of the job market, low inflation, and the record or near-record levels of corporate profits.

And a final point to consider: How would Trump interpret a potential reversal in the stock market’s recent fortunes?

"When the stock market rises, it's great to take credit," Michael Yoshikami, founder and CEO of Destination Wealth Management, told CNBC. "But will someone take credit if the market goes down? There probably would be not credit but more blame."