New Yorkers are proving to be cost conscious when choosing a private health insurance plan from New York State of Health, the marketplace created by the Affordable Care Act, which has now enrolled more than 10 percent of state residents. Of the 2.1 million enrollees, 415,352 chose a private plan, 1,568,345 signed up for Medicaid and 159,716 enrolled in Child Health Plus, according to an enrollment report released Wednesday by the state's health department.