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U.S. President Donald Trump waves as Ivanka Trump (L) and U.S. Treasury Secretary Steven Mnuchin look on prior to the morning working session on the second day of the G20 economic summit on July 8, 2017 in Hamburg, Germany. (Sean Gallup/Getty Images)

In the week leading up to the G20 Summit in Hamburg, Germany, with a much-anticipated meeting with Russia's Vladimir Putin casting a shadow over an investigation into Russia's meddling in the 2016 presidential election, President Donald Trump finds himself mired by historically low approval numbers.

Trump’s approval numbers have been hovering around or just below 40 percent after they dipped into the mid-30s last month following the firing and subsequent testimony of FBI Director James Comey. Those numbers had climbed back to around 40 percent but have dipped just below that after a series of insulting tweets towards MSNBC host Mika Brzezinski last week.

In the last week, Trump's approval numbers had been just below 40 percent amid the continuing investigations by Congress, the Senate, and Special Counsel Robert Mueller, who are investigating Trump for obstruction of justice for firing Comey and Trump's campaign dealings with the Russian government during the 2016 presidential election.

READ: Trump Approval Ratings: Low Support Amid Controversial Tweets And Senate Delaying Healthcare Vote

Three polls of Trump's approval rating were taken this week: Rasmussen, Gallup and SurveyMonkey. All three showed the president’s disapproval marks outweighing his approval marks, while his approval stays around the high 30s or low 40s.

In the Rasmussen Report, a historically right-leaning tracking poll, the president got his highest approval rating, 45 percent, between July 4 and July 6, falling one point from last week. The FiveThirtyEight tracking aggregator, which weighs the polls by historic leanings, adjusted that percentage down to 40 percent. By contrast, the approval tracker showed a 55 percent disapproval rating.

In a Gallup Poll taken between July 3 and July 6, Trump's approval rating was in the high 30s, receiving a 37 percent approval and 57 percent disapproval rating. These numbers continue the downturn in support from the prior week that showed the president at 38 percent approval. The Gallup Poll was adjusted to 38 percent approval and 56 percent disapproval rating.

A SurveyMonkey poll taken between June 30 and July 5 was in between the Gallup poll and Rassmussen poll, with 43 percent approval and 55 percent disapproval, adjusted to 41 percent approval and 54 percent disapproval. This is a slight uptick in approval from last week's numbers.

The FiveThirtyEight aggregator averages 39.0 percent approval and 55.1 percent disapproval, which has shown the president's approval maintaining similar support numbers going into the G20 summit, Trump's controversial Twitter postings and the lingering Russian investigation.

READ: Trump's Approval Rating Hits 36 Percent Low In New Poll Amid Russia Investigation

On RealClearPolitics poll aggregator for "Trump's Favorability" and "Direction of the Country," there has been a similarly low level of support for the president. His favorability is at 40.4 percent and his unfavorability is at 53.6 percent. An average of only 33 percent of Americans thinks the country is going in the right direction, while 59 percent think the country is going in the wrong direction.