The federal government says nearly 28,000 Arizonans have picked plans under the Affordable Care Act health care exchange in the first three months of open enrollment. The figures were released Monday by the United States Department of Health and Human Services. More than $2 million people have signed up nationally. Most of those signing up for coverage in Arizona are older. The department says that 36% of those that have chosen plans are between ages 55 and 64. At 53%, slightly more women have chosen plans than men in Arizona. 68% are getting financial help to pay their monthly premium.