Though parents might be rejoicing that the time has come for their kids to head back to school, their happiness could be tempered by a little-known fact: They’re paying import taxes on everything from clothes to lunchboxes, musical instruments to pencils.

In 2010, the government collected $25.9 billion in tariffs on imported items. Shoppers paid a total of $13.9 billion in tariffs on products like jeans, t-shirts, and tennis shoes. Tariffs are a hidden tax that increases the price of many popular back-to-school items. In the chart below, you can see a breakdown on what is taxed–and by how much.