Gallup on Wednesday announced it will start updating its presidential job approval polls on a weekly basis instead of a daily basis.

"We are making this change largely because the source for these daily data, the Gallup Daily tracking program — made possible by a client-supported commitment to daily interviewing on a wide variety of well-being metrics — is shifting from telephone surveys to reporting mail surveys on a monthly basis," said the 83-year-old D.C.-based firm on its website.

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"Gallup remains committed to tracking presidential approval using probability-based, telephone interviewing, but is reducing the sample size from 3,500 to 1,500 U.S. adults per week. As a result, Gallup will aggregate and report presidential job approval each week, rather than daily, beginning on Jan. 8 at 1 p.m. ET," it continued.

"We will continue to report subgroup differences for presidential job approval using the large sample sizes collected each month."

Gallup was founded by George Gallup in 1935.

In addition to political polling, it also "delivers analytics and advice to help leaders and organizations solve their most pressing problems," according its website.

The decision comes as President Trump Donald John TrumpHR McMaster says president's policy to withdraw troops from Afghanistan is 'unwise' Cast of 'Parks and Rec' reunite for virtual town hall to address Wisconsin voters Biden says Trump should step down over coronavirus response MORE's weekly job approval rating on Gallup hit its highest point in months.

The firm reported that Trump's weekly job approval rate was at 39 percent during the last week of December, which came just after the president signed the GOP tax-reform bill into law.

The last time Trump's weekly approval was at 39 percent was in July, according to Gallup.

He had a high of 45 percent just after his inauguration in January.