The first U.S. Census, in 1790, required delivery via horseback. The data consisted of the name of each head of household, the number of white males, number of free white females, other free persons, and slaves. The population was 3.9 million. The current population is about 330 million, according to the Census Bureau.

More questions were added during the 1800s about age and country of origin. Categories for race were limited to white, black and mulatto. In 1850, free persons were listed individually instead of by family. Slaves were listed as numbers, not names, by owner. In 1870, race categories were expanded to include Chinese, which encompassed all east Asians, and American Indians. Questions were also added about education, literacy, profession and place of birth.

In 1930, the racial classification changed. Whenever a person had any fraction of white ancestry, he or she was to be reported as white. For the first and only time, “Mexican” was listed as a race. In 1940, all households answered 16 questions. A sample of additional households received a long form with questions regarding socioeconomic information. That methodology continued through the 2000 census.

In 1970, for the first time, households were allowed to self-report. Until then, all surveys were collected by enumerators.

In 2010, the census bureau innovated again. All households answered just 10 questions. Rather than survey one household in six for more detailed information via a long form, the Census Bureau used the data collected by the American Community Survey, sent to about 3.5 million people each year since 2005.

The 2020 census questions are identical to those of 2010. The U.S. Supreme Court did not allow adding a question about citizenship. Those opposed to adding the question feared that it would have a negative impact on the willingness of some to complete the census. The court ruled that executive branch officials must “offer genuine justifications for important decisions, reasons that can be scrutinized by courts and the interested public,” and said the explanation offered by the Trump administration for adding the question “appears to have been contrived.”

Gender on the 2020 form is simply male or female and is self-identified. If the household includes a spouse or non-married partner, they are asked to identify as same-sex or opposite-sex. Some LGBTQ advocates want to add additional questions about gender and identity to better identify needed resources.