If you\'re at a coffee shop, anywhere in Philadelphia, or if it\'s late at night, hang on to your smartphone. Losing your smartphone can be stressful, given how much important data and access to services a typical one contains. On average, people lose their smartphone once per year, according to Lookout Mobile Security. Recently, Lookout analyzed phone loss data and found some interesting trends about where and when people lose their phones. This data is presented on a new interactive website, Mobile Lost and Found. Lookout gathered data from its mobile security app, which is on more than 15 million cell phones around the world (mostly Android phones). In 2011, Lookout found 9 million smartphones. (The company considered a phone as having gone missing whenever a user logged in to Lookout via the Web to find a phone.) \"Losing your phone is absolutely the biggest mobile security risk cell phone owners currently face, even more than malware,\" said Kevin Mahaffey, Lookout\'s chief technology officer. \"People lose their phones in the places they go every day. It\'s not a stray comet from the sky snatching your phone. That\'s why we wanted to study this.\" When are people most likely to lose their phone? Lookout found that the vast majority of smartphone losses happen late at night, from 9 p.m. to 2 a.m. Looks like nightlife may be a culprit. But on holidays, or during major events such as festivals or big sporting events, people are especially likely to lose a phone. In 2011, phone losses around the world spiked on Christmas and New Year\'s Eve. And on February 27, 2011, phones in Dublin, Ireland, were lost at nearly three times the normal rate during a major international rugby tournament there. In general, throughout the United States, the five types of places where people are most likely to lose a cell phone are coffee shops, bars, restaurants, at the office or at home. Also, the five U.S. cities where people are most likely to lose a smartphone are Philadelphia; Seattle; Oakland, California.; Long Beach, California; and Newark, New Jersey. Mahaffey observed that several of the top phone-losing cities also have high crime rates, but that doesn\'t necessarily mean that more phones are stolen in these cities. Lookout\'s data does not indicate what actually happened to those missing phones -- how many were stolen vs. lost, or how many were eventually found. That might be a subject for future Lookout research, he said.