LGBTQ advocacy groups are outraged after proposed questions regarding sexual orientation and gender identity were quickly removed Tuesday from a just-released draft of the 2020 U.S. Census.

The U.S. Census Bureau, which is part of the Department of Commerce, is required to issue a list of categories it plans to track three years before the survey is conducted. Tuesday's list showed categories ranging from race and gender to the type of plumbing in homes and the length of a person's daily commute to work. Each category is followed by a table showing the federal agencies that rely on the data to make decisions about law enforcement, health care, equal employment opportunities and more.

No previous U.S. Census has ever included LGBTQ Americans, which makes it challenging for federal agencies and researchers to accurately track the size, demographics and needs of the community. In addition, the more detailed American Community Survey also leaves out LGBTQ categories. Tuesday's initial release from the Census Bureau proposed including lesbian, gay, bisexual, and transgender people on both surveys.

Advocacy groups have been campaigning for years to include questions about sexual orientation and gender identity, and were briefly elated when the 2020 Census draft was released. But hopes were dashed when the proposed addition suddenly disappeared, and a statement was issued by the Census bureau that called the LGBTQ inclusion a mistake.

"The Subjects Planned for the 2020 Census and American Community Survey report released today inadvertently listed sexual orientation and gender identity as a proposed topic in the appendix," the U.S. Census Bureau said in a statement to NBC News. "This topic is not being proposed to Congress for the 2020 Census or American Community Survey. The report has been corrected."

The National LGBTQ Task Force published both versions of the 2020 Census plan to its website, showing the removed row in the “Subjects Planned for the 2020 Census and American Community Survey” section.

Illustration: The National LGBTQ Task Force http://www.thetaskforce.org/sexual-orientation-and-gender-identity-erased-from-2020-census-and-the-american-community-survey-acs/

"If the government doesn’t know how many LGBTQ people live in a community, how can it do its job to ensure we’re getting fair and adequate access to the rights, protections and services we need?" Meghan Maury, Criminal and Economic Justice Project Director at the National LGBTQ Task Force, asked in a statement Tuesday.

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Maury told NBC News her organization plans to ask Congress for an oversight hearing, demanding answers from the Trump administration about why the category was suddenly removed.

"The National LGBTQ Task Force will continue to push for accurate data collection on LGBTQ people," Maury added. "Whether it's through lobbying for legislation in Congress, pushing the administration to adopt new policies or serving on the U.S. Census Bureau's National Advisory Committee on Racial, Ethnic and Other Populations."

The removal of the LGBTQ category came just over a week after the Trump administration removed questions about LGBTQ senior citizens from the National Survey of Older Americans Act Participants. Those questions, which helped determine funding for groups that work with older LGBTQ Americans, had been added to the annual survey in 2014.

The push to tally LGBTQ Americans in the census has been ramping up in recent years. In April 2016, a bipartisan group of nearly 80 members of Congress asked that the census and the American Community Survey add questions about sexual orientation and gender identity.

In 2009, the National LGBTQ Task Force launched a campaign encouraging LGBTQ people to place "Queer the Census" stickers on their survey packets when they mailed them back to the government. According to the Task Force, more than 100,000 LGBTQ people included the sticker on their 2010 census envelopes.

In a statement, GLAAD president Sarah Kate Ellis said the census confusion was just the latest in a series of Trump administration moves against the LGBTQ community—starting with the immediate removal of all LGBTQ-related content from the White House website on January 20 and continuing with moves to roll back protections for transgender students, remove LGBTQ people from two other federal surveys and cut funding for HIV/AIDS research.

“By erasing LGBTQ Americans from the 2020 U.S. Census, the Trump Administration is adding a disgusting entry to a long list of tactics they’ve adopted to legally deny services and legitimacy to hard-working LGBTQ Americans," Ellis said.

NBC News reached out to the White House for comment and was told through email, "Since this simply is a mistake, as Commerce explained in their statement, we won't be commenting any further."

On Wednesday afternoon, U.S. Census Bureau Director John H. Thompson posted a statement on the bureau’s blog addressing the “error."

“There have been a number of questions raised about the inclusion of sexual orientation and gender identity due to an error in the appendix of the report. Our proposal to Congress was that the planned subjects remain unchanged from the 2010 Census and will cover gender, age, race/ethnicity, relationship and homeownership status. It did not include sexual orientation or gender identity,” Thompson stated.

"In April 2016, more than 75 members of Congress wrote to the Census Bureau to request the addition of sexual orientation and gender identity as a subject for the American Community Survey. We carefully considered this thoughtful request and again worked with federal agencies and the [Office of Management and Budget] Interagency Working Group on Measuring Sexual Orientation and Gender Identity to determine if there was a legislative mandate to collect this data. Our review concluded there was no federal data need to change the planned census and ACS subjects,” Thompson's statement continued.

Editor's Note: The original version of this article was updated to include a statement from the director of the U.S. Census Bureau.

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