More than 200 trauma centers have opened since 2009 in more than 20 states, and another 75 hospitals are seeking approvals, according to data collected by Kaiser Health News from state health agencies. States with the greatest number of new centers include Texas, Alabama, Arizona and California. The growth reverses more than a decade of closures in the 1990s and early 2000s. Leading the trend is Nashville-based HCA, according to state data. Since 2009, it has added or is planning to add about 20 trauma centers, including almost a dozen in Texas and Florida, as part of an expansion of its emergency room business. Another for-profit hospital chain, Community Health Systems, added seven trauma centers in the past three years.