Notwithstanding the concentration of elite medical centers in the state, The Commonwealth Fund ranks the Texas healthcare system the third worst in the nation. Texas ranks close to last in access to healthcare, quality of care, avoidable hospital spending, and equity among various groups. Causes of the state's poor rankings include politics, a high poverty rate, and the highest rate of illegal immigration in the nation. In May 2006, Texas initiated the program "code red" in response to the report the state had 25.1 percent of the population without health insurance, the largest proportion in the nation.