The U.S. Census Bureau is mailing a second round of census questionnaires to about 40 million households in hopes of reducing the estimated $2.7 billion cost of sending census takers out to nonresponsive households.

The forms are being sent to areas that had below-average response rates in the 2000 Census.

The second round of mailings is expected to increase the mail participation rate by up to 10 percentage points, resulting in a savings of more than $500 million, according to Census Bureau Director Robert Groves.

According to the Census Bureau, it costs the government 42 cents when forms are returned in the mail, compared to $57 to count a household that fails to return a form via mail.

In Hawai'i, census takers will begin visiting homes that have not returned a census form beginning in May.

As of yesterday, 62 percent of census forms mailed nationwide had been returned.

Hawai'i, which had the third-lowest mail response rate (60 percent) in the 2000 Census, is again near the bottom in mail participation this year.

The state is tied with New York, Oklahoma and Texas at 56 percent, ahead of only Alaska (51 percent), New Mexico (54 percent) and Louisiana (55 percent).

U.S. territory Puerto Rico has a mail response rate of 45 percent so far.

Wisconsin leads the nation in mail responses at 74 percent, followed by Iowa and Minnesota (72 percent).