In a few weeks, every household in Michigan and across the nation will receive a very important piece of mail: a 2010 Census form. It is not an exaggeration to say that filling out your census form is a civic duty, the responsibility of each of us to our state and nation.

The Constitution mandates that once a decade, the government undertake a census. The primary purpose of the census is to determine the number of members each state has in the House of Representatives. The population counts from the census are also used to draw the district boundaries for the U.S. House and state House and Senate. This is especially important for Michigan, which is at risk of losing a U.S. House seat, a loss that would weaken our state’s voice in Congress and a vote in the Electoral College that chooses our president.

But that’s not all. More than $400 billion in federal funding for a host of programs is determined in part by census population counts. That means funding for your local hospital, the highway you take to work every morning, the schools your children attend and the police and fire agencies that protect you and your family are at stake.

Census data is critical to the work of members of Congress, the president and his advisers, and other policy-makers. We can only make informed policy decisions if we have an accurate picture of where our nation stands.

And it’s not just government that uses census data. Medical researchers use census information to help investigate the spread of diseases. Businesses use it to find customers and to locate skilled workers. Academic experts and the news media use it to understand and explain our nation and how it is changing.

For all these reasons, responding to the census is important for all of us. Luckily, it’s not at all hard to do.

Your household soon will receive a questionnaire in the mail. It asks 10 simple questions about you and your family, and should take about 10 minutes to complete. Fill out the questionnaire, mail it back in the postage-paid envelope provided, and your civic duty is done. If you forget, you will receive a follow-up questionnaire, and if you don’t send in a questionnaire, a census worker may visit your home in person to get your responses. However you provide your information, it’s important to do so, but responding to the questionnaire is the best way to ensure an accurate count.

In past census years, you may have received something known as the “long form” questionnaire, which asked more detailed questions. In 2000, one in six households received the long form. The information gathered in the past using this form is now compiled in a separate survey, the American Community Survey. If you are one of those contacted by the American Community Survey, it’s important to take the few minutes to participate.

Please keep in mind as you fill out your census survey that the information you provide is 100 percent confidential – the census is designed to compile statistical data, not information on individuals or their families. It is a violation of federal law, punishable by stiff fines and jail time, to disclose anyone’s responses to census questions – no one, not even other federal agencies, has access to your responses.

Michigan has a history of doing its part in the census. In 2000, Michigan ranked among the top 10 states in returning census questionnaires. I’m proud of that, and hopefully we can meet or exceed that rating this year, because so much is at stake. When you send in your census form, you will be doing your part to help your family, your community, Michigan and the nation.

Carl Levin is the senior U.S. senator from Michigan.