Mobile security firm Lookout Labs based its findings on data from 15 million users who downloaded its app that locates lost devices.
The Top 5 cities in the United States for phone loss in 2011 were Philadelphia; Seattle; Oakland, Calif.; Long Beach, Calif.; and Newark, N.J., the report said.
Four of the 10 cities with the highest rates of lost and stolen phones -- Cleveland, Detroit, Oakland and Newark -- also were among the 10 cities with the highest crime rates, Lookout Labs said.
The company said its app located 9 million lost smartphones last year, or one phone every 3.5 seconds.
"Each day, $7 million worth of phones are lost by Lookout users alone, and if unrecovered, it would take a significant toll not only on our wallets, but on our psyche, too," Kevin Mahaffey, co-founder of Lookout, told USA Today.
People are most likely to lose a phone at night, with a majority of lost phones being located between 9 p.m. and 2 a.m., the company said, and phones were most often lost at coffee shops, bars, workplaces and restaurants.
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