Americans reportedly spend more than $5 billion upgrading their iPhones, or switching to Apple from a competing brand, each year. Just to put this number in some context, it essentially means that Apple could afford to pay for its new Apple 2 campus based wholly on iPhone upgrades for a single year.

The average iPhone upgrade costs $151 every two years, which works out to $5.4 billion in upgrades every year, according to the study by SellCell.com, a site that aggregates deals from more than 20 trade-in companies. “We’re a nation of mobile-phone lovers — obsessed with getting a shiny new device,” says Craig Timmins, spokesman for SellCell.com. AppleAAPL +3.54%  accounts for 41% of the U.S. smartphone market, according to market research firm ComScore, and iPhone owners pay more than the average price to upgrade ($130). In fact, Americans spend over $11 billion upgrading all types of smartphones annually, and nearly one in four U.S. adults (23%) upgrades his or her phone each year.