If you routinely stop for coffee, make sure you have your cell phone with you when you leave. A new study reveals coffee houses are the most likely places to lose a phone or have it stolen — especially if you live in Philadelphia.

Mobile security firm Lookout reports Americans lose their phones once a year on average, and the company’s co-founder and chief technology officer, Kevin Mahaffey, said, “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.”

Using its own figures and data pulled from social check-in site Foursquare, Lookout compiled a list of the places and cities all those phones are likely to go missing. So where do you need to be extra-vigilant?

Here are the top 10 places your phone is most likely to vanish:

  1. Coffee houses
  2. Bars
  3. Offices
  4. Restaurants
  5. Apartments and condominiums
  6. Grocery stores
  7. Gas stations
  8. Residential
  9. Pharmacies or drugstores
  10. Parks

And here are the cities in which a phone is most likely to go missing:

  1. Philadelphia
  2. Seattle
  3. Oakland, Calif.
  4. Long Beach, Calif.
  5. Newark, N.J.
  6. Detroit
  7. Cleveland
  8. Baltimore
  9. New York
  10. Boston