The annual output of minted copper currency in 1085 reached roughly six billion coins. The most notable advancement in the Song economy was the establishment of the world's first government issued paper-printed money, known as Jiaozi (see also "Huizi"). For the printing of paper money, the Song court established several government-run factories in the cities of Huizhou, Chengdu, Hangzhou, and Anqi. The size of the workforce employed in paper money factories was large; it was recorded in 1175 that the factory at Hangzhou employed more than a thousand workers a day.