In 2001, the US Mint stopped minting them for regular circulation, and now only produces them for collectors (proof and mint sets, rolls and bags.). Basically, what happened with the ½ dollars is that up until 1964, dimes, quarters and half dollars were minted in silver, but the melt value of silver rose higher than the face value of the coins. They switched dimes and quarters to copper nickel clad, but from 1965 until 1970, they continued to mint half dollars in a 40% silver clad combination because of the higher value, and because of that and because of sentimental reasons (Kennedy first appeared on the ½ dollar in 1964), people began to hoard them. By the time the mintage matched the demand for the coins, the mint switched to the cupro-nickel composition (in 1971), and by then, people had lived 7 years with a shortage and had learned to adapt to using quarters. Many banks stopped stocking them due to lack of demand once they no longer had any precious metals in them, and vending machines began to be manufactured without the capability of accepting them because no one who had them would spend them. Therefore, once they had enough to go into circulation and were of a composition that people were willing to spend, no one really wanted them, they were hard to come by AND harder to use than quarters, plus everyone was so used to using quarters. Because they do get issued in bags and rolls for collectors, some times post 2001 halves end up in circulation, but it’s pretty rare, if you get one, hang onto it.