On Census Day Wednesday, Minnesota and Wisconsin were virtually tied for the nation's highest share of households that have responded to the 2020 Census so far.

Just over 46% of households in both states had already answered the short questionnaire, mostly online, but some over the phone or on a paper questionnaire, as of Wednesday. It's well above the national average of 38%.

As the reference date for the once-a-decade head count, Census Day is a crucial part of a process that determines congressional representation and dictates where millions of dollars will be spent for safety-net programs.

Each household is asked to fill out one questionnaire about the people living there as of April 1, such as each person's age, gender, race, Hispanic ethnicity and relationship to the head of household.

Most households already received one, if not two, letters from the Census Bureau directing them how to go online or via phone to complete the questionnaire. About 3% of Minnesota households, primarily those that receive their mail via post office boxes or those living on tribal lands, would not have gotten those letters.

Unlike in years past, the Census Bureau is avoiding mailing paper forms to every household. Forms will be mailed out between April 8 and 16 to households that have yet to respond.

"There are so many things being done differently this time," said Minnesota State Demographer Susan Brower.

On Wednesday morning Brower's office, in conjunction with many counties, pushed out a text alert to about 1.3 million Minnesota registered voters, encouraging them to fill out the form.

Census Bureau officials are particularly keen this year to get as many responses as possible from the mailings. Reaching out to people via telephone or sending census workers out to knock on doors is time-consuming and costly. In-person visits are especially problematic because of the COVID-19 pandemic.

Rallies, door-knocking and other events encouraging people to fill out their forms that had been planned for this week were canceled due to the coronavirus. Brower said groups in Minnesota that are working to promote full participation are switching to phone calls.

Drilling down to the county level in the self-response rate, data show wide variations, but areas with the lowest rates are those where the Census Bureau sent fewer letters and will instead rely on census takers to either hand-deliver paper forms or gather answers in person.

This is especially apparent in the northern Minnesota counties of Mahnomen, Cook, Lake of the Woods and Cass, which are all below 20%.

Census takers are scheduled to start knocking on doors on May 28 at the earliest, but that could still be delayed further, Brower said. People who live in those counties are still welcome to fill out the online form (at 2020census.gov) anytime.

Minnesota's Rock County was the first to eclipse a 50% response rate and is now nearing 54% In fact, most of southern Minnesota was quick to respond.

"I know the census is not surprising folks in southern Minnesota," Brower said. "There's been a lot of good work going on there, over the last year, to let people know about it."

Four Wisconsin counties — Washington, Calumet, Ozaukee and Waukesha — have the highest rates among all U.S. counties, all just above 55%. Minnesota's Carver County is also in the top 20, with about 54%.

Minnesota officials are especially concerned with participation because the state is forecast to possibly lose a congressional seat because its population growth hasn't kept pace with states like Florida and Texas that are poised to gain seats. Making sure everyone is counted gives the state a better shot at avoiding that.

Minnesota and Wisconsin led the nation in the 2010 Census with about 74% of households returning the mail-in questionnaires.

The U.S. Census Bureau publishes daily updates on its website showing these self-response rates, measuring the percentage of households that have responded so far without interventions by census workers. View 2020 response rates for states, counties and even census tracts at 2020census.gov/en/response-rates.html.