Births far outpace deaths. In 2007, there were 122,579 birth and 19,439 deaths. Approximately 85% profess the Catholic faith. Demographically, Oaxaca stands out due to the high percentage of indigenous peoples. It is estimated that at least a third are speakers of indigenous languages (with 50% not able to speak Spanish), accounting for 53% of Mexico's total indigenous language speaking population. The state straddles two Mesoamerican cultural areas. The first extends into the state from the Mayan lands of Chiapas, Yucatán and Guatemala. The central and northwest of the state is part of the cultures of the Valley of Mexico, with historical influence seen from ancient cities such as Teotihuacan, Tula and Tenochtitlan. The main reason that indigenous languages and cultures have been able to survive here is the rugged terrain, which isolate communities. This also has the effect of dividing the state into small secluded communities, which have developed independently over time. There are 16 ethno linguistic groups recognized by the Instituto Nacional Indigenista who maintain their individual languages, customs and traditions well into the colonial period and to some extent to the present day. However, some studies put the number of cultures in the state as high as 4,000. This makes Oaxaca the most ethnically complex of Mexico's 31 states. The most populous indigenous groups in Oaxaca are the Zapotec or Mixtec. Several other languages of the Oto-Manguean languages are spoken in Oaxaca: The Triques, Amuzgos and Cuicatecs are linguistically most closely related to the Mixtecs, The languages of the Chocho, Popoloca and Ixcatec peoples are most closely related to that of the Mazatecs. The Chatino language is grouped with the Zapotecan branch of Oto-Manguean. The languages of the Zoque and Mixe peoples belong to the Mixe–Zoquean languages. Other ethnic groups include the Chontalees, Chinantecs, the Huaves and Nahuas. As of 2005, a total of 1,091,502 people were counted as speaking an indigenous language. The largest indigenous group in the state are the Zapotecs at about 350,000 people or about 31% of the total indigenous population. The Zapotec have an extremely long history in the Central Valleys region and unlike other indigenous groups, do not have a migration story.