Villaraigosa pointed out the 2000 Census undercounted the city's population by about 78,000 people, and that miscalculation caused the city to miss out on $200 million in federal funding.
The mayor said the 2010 Census will form the foundation of the number of representatives sent to Washington, the amount of money families get for health care, and school resources.
Thousands of volunteers from the U.S. Census Bureau will begin the work on Monday of verifying more than 145 million addresses and identifying every space where people live or could potentially live.
Nine years ago, the most undercounted people included young children, minorities, recent immigrants, the homeless and renters.
"We're sending the message loud and clear, every person counts," Villaraigosa said.
The U.S. Constitution requires that a national census be completed every 10 years.
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