Population data was obtained at the county level from the Texas Department of State Health Services (TDSHS, <a href="http://www.dshs.state.tx.us/chs/popdat/default.shtm">
http://www.dshs.state.tx.us/chs/popdat/default.shtm</a>). TDSHS estimates were used over US Census values so that population
data could be compared with other datasets (which were collected in years the US Census did not occur - 1997, 2002, and 2007)
in the Texas Land Trends study. TDSHS and US Census data may vary slightly. <br />