Volunteer Letricia Brown, center, interviews homeless people living under a bridge, Friday, Jan. 17, 2014. The volunteers are recording data during "Registry Week" to document homelessness for the Miami-Dade County Homeless Trust.The county is part of a national movement called the "100,000 Homes "campaign which aims to find permanent homes for the most chronic and vulnerable homeless. (AP Photo/Lynne Sladky)

WASHINGTON -- Since the Great Recession, many American cities have sought to eradicate homelessness not so much by giving people shelter, but by making it illegal to be homeless.

Citywide bans on things that homeless people need to do to survive are on the rise, according to a new report by the National Law Center on Homelessness & Poverty. Key findings from the center's survey of 187 U.S. cities show that since 2011:

Citywide bans on camping in public have increased by 60 percent.

Citywide bans on begging have increased by 25 percent.

Citywide bans on loitering, loafing, and vagrancy have increased by 35 percent.

Citywide bans on sitting or lying down in particular public places have increased by 43 percent.

Bans on sleeping in vehicles have increased by 119 percent.

"There is a severe shortage of affordable housing and a lack of emergency shelter options in our communities, leaving homeless people with no choice but to perform basic acts of survival in public spaces," law center director Maria Foscarinis said in a press release.

"Despite a lack of any available alternatives, more cities are choosing to turn the necessary conduct of homeless people into criminal activity," Foscarinis continued. "Such laws threaten the human and constitutional rights of homeless people, impose unnecessary costs on cities, and do nothing to solve the problems they purport to address."

The federal government's most recent annual headcount shows homelessness declining 9 percent from January 2007 through January 2013, with 65 percent of the nation's 610,042 homeless people staying in shelters on a given night that month. Unsheltered homelessness declined by 23 percent over those years, according to the government's count.

The law center's report begs to differ from the government's data, noting that it fails to account for several factors, including that some homeless people are in jail when the survey happens. Other data suggest worsening homelessness, such as a recent report from the U.S. Conference of Mayors, which found a 4 percent increase in family homelessness from 2012 to 2013.

The law center's report highlights several individual stories, including that of Lawrence Lee Smith, a Boise, Idaho, man who is a plaintiff in a case against the city's anti-camping ordinance. Degenerative disk disease had made Smith unable to work, and he had nowhere to go after the city towed his camper.