Though Sweden has had a standard glass bottle recycling system since 1884, in response to the increased litter from single-use containers, container deposit laws have been adopted in many developed countries (sometimes by provincial and municipal governments) starting in the 1970s. These laws mandate that retailers must charge a deposit on certain types of containers or for certain products; retailers are then required to accept empty bottles or cans for recycling and refund the deposit. A government fund mediates any imbalances caused by buying containers at one retailer and returning them to another, and also retains the profit from unreturned containers.