Task: Question Understanding
Input (English): Passage: After 1960 public sector unions grew rapidly and secured good wages and high pensions for their members. While manufacturing and farming steadily declined, state- and local-government employment quadrupled from 4 million workers in 1950 to 12 million in 1976 and 16.6 million in 2009. In 2009 the U.S. membership of public sector unions surpassed membership of private sector unions for the first time, at 7.9 million and 7.4 million respectively. In 2011 states faced a growing fiscal crisis and the Republicans had made major gains in the 2010 elections. Public sector unions came under heavy attack especially in Wisconsin, as well as Indiana, New Jersey and Ohio from conservative Republican legislatures. Conservative state legislatures tried to drastically reduce the abilities of unions to collectively bargain.  Conservatives argued that public unions were too powerful since they helped elect their bosses, and that overly generous pension systems were too heavy a drain on state budgets.
Question: Which year had the most workers?
Output (English): date