Although until the 1960s, many indigenous communities were considered by scholars to be autonomous and economically isolated, this was never the case. Economic conditions began forcing many to migrate to work, especially in agriculture for non-indigenous. However, unlike many other migrant workers, most indigenous in Chiapas have remained strongly tied to their home communities. A study as early as the 1970s showed that 77 percent of heads of household migrated outside of the Chamula municipality as local land did not produce sufficiently to support families. In the 1970s, cuts in the price of corn forced many large landowners to convert their fields into pasture for cattle, displacing many hired laborers, cattle required less work. These agricultural laborers began to work for the government on infrastructure projects financed by oil revenue. It is estimated that in the 1980s to 1990s as many as 100,000 indigenous people moved from the mountain areas into cities in Chiapas, with some moving out of the state to Mexico City, Cancún and Villahermosa in search of employment.