Because of its high rate of economic marginalization, more people migrate from Chiapas than migrate to it. Most of its socioeconomic indicators are the lowest in the country including income, education, health and housing. It has a significantly higher percentage of illiteracy than the rest of the country, although that situation has improved since the 1970s when over 45% were illiterate and 1980s, about 32%. The tropical climate presents health challenges, with most illnesses related to the gastro-intestinal tract and parasites. As of 2005, the state has 1,138 medical facilities: 1098 outpatient and 40 inpatient. Most are run by IMSS and ISSSTE and other government agencies. The implementation of NAFTA had negative effects on the economy, particularly by lowering prices for agricultural products. It made the southern states of Mexico poorer in comparison to those in the north, with over 90% of the poorest municipalities in the south of the country. As of 2006, 31.8% work in communal services, social services and personal services. 18.4% work in financial services, insurance and real estate, 10.7% work in commerce, restaurants and hotels, 9.8% work in construction, 8.9% in utilities, 7.8% in transportation, 3.4% in industry (excluding handcrafts), and 8.4% in agriculture.