If you think getting an accurate count of the U.S. population is a daunting task, consider the job in India. About 2.5 million census takers on Thursday began the work of photographing and fingerprinting that country’s population, estimated at over a billion people.

There are no forms to be mailed back for the Indian census. Over the next year, the census takers will visit every building that serves as a dwelling in the entire country. They will also note the availability of toilets, drinking water and electricity, amenities we are thankful to take for granted. And they will collect information on Internet, mobile phone and bank account usage, questions our census would not dare ask.

Looking at India’s census puts our own in perspective. The U.S. Census form asks only how many people live in the home; whether they live there all the time; their names, ages and sex; their race; whether they are Hispanic; whether the resident owns the home, makes mortgage payments, rents or lives there for free; and a contact phone number.

The Census Bureau Web site 2010.census.gov lists the questions and explains why each one is included. You can see what the form looks like on the site, but you can’t print it and you can’t fill it out online. That probably will be available by the 2020 census, but this year, we all still have to use paper forms.

The forms were mailed in March to households that accept mail at their street addresses. If you get your mail at the post office, you have to either pick up a form at a place designated in your community or wait for a census worker to visit you.

All the forms and interviews are to be complete by the end of July. In December, the Census Bureau will deliver the results of the population count to President Obama, and in March 2011 it will send the states their redistricting information.

Although shifting the congressional districts is the most visible result of the census, it is not the only reason for conducting it. The census tells how many of us there are and where we are concentrated, which groups are growing and which are shrinking. With billions of federal dollars at stake for such services as education, health care, job training and highway construction, local officials are stretching their creativity to persuade you to make sure you are counted.

It’s as important as voting.