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. 2016 Nov 14;6:36958. doi: 10.1038/srep36958

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Copyright © 2016, The Author(s)

This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

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A number in parentheses is the number of overall sample size. Error bars represent 95% confidence intervals. The map was created with ArcGIS software, version 10.4, http://www.esri.com.