Do you have an unused gift card that you received on Christmas, a birthday, or any other occasion? A surprising number of gift cards are going to waste, according to a new survey.

The survey, from online financial advisory services provider Credit Summit, found at least half of those surveyed admitted losing a gift card before they used it. The survey says about two-thirds of people who responded had at least one unspent gift card worth $200 or less. Credit Summit reports there is as much as $21 billion worth of unused or lost gift cards lying around.

Gift cards don't expire until at least five years from the activation date, according to federal law. If you have an unwanted gift card, there are some websites where you can sell, trade, or donate them.