Dairy farming is the primary source of agricultural income. In the second half of the 20th century, developers had plans to build condos and houses on what was relatively inexpensive, open land. Vermont's government responded with a series of laws controlling development and with some pioneering initiatives to prevent the loss of Vermont's dairy industry. Still, the number of Vermont dairy farms has declined more than 85% from the 11,206 dairy farms operating in 1947. In 2003 there were fewer than 1,500 dairy farms in the state; in 2006 there were 1,138; in 2019 there were 658. The number of dairy farms has been diminishing by 10% annually. 80% of open land is controlled by dairy farms.