rate on average in the first quarter of 2016, while those that did not had a 14.1% uninsured rate, among adults aged 18–64. As of December 2016 32 states (including Washington DC) had adopted the Medicaid extension. A 2017 study found that the ACA reduced socioeconomic disparities in health care access. Taxes Excise taxes from the Affordable Care Act raised $16.3 billion in fiscal year 2015. $11.3 billion came from an excise tax placed directly on health insurers based on their market share. Annual excise taxes totaling $3 billion were levied on importers and manufacturers of prescription drugs. The Individual mandate tax was $695 per individual or $2,085 per family at a minimum, reaching as high as 2.5% of household income (whichever was higher). The tax was reduced to 0 at the end of 2018. In fiscal year 2018, the individual and employer mandates yielded $4 billion each. Excise taxes on insurers and drug makers added $18 billion. Income tax surcharges produced 437 billion. PPACA reduced income inequality measured after taxes, due to the income tax surcharges and subsidies. CBO estimated that subsidies paid under the law in 2016 averaged $4,240 per person for 10 million individuals receiving them, roughly $42 billion. The tax subsidy for the employer market, was approximately $1,700 per person in 2016, or $266 billion total. Insurance exchanges As of August 2016, 15 states operated their own health insurance marketplace. Other states either used the federal exchange, or operated in partnership with or supported by the federal government. By 2019, 12 states and Washington DC operated their own exchanges. Medicaid expansion As of December 2019, 37 states (including Washington DC) had adopted the Medicaid extension. Those states that expanded Medicaid had a 7.3% uninsured rate on average in the first quarter of 2016, while the others had a 14.1% uninsured rate, among adults aged 18 to 64. Following the Supreme Court ruling in 2012, which held that states would not lose Medicaid funding if they didn't expand Medicaid under PPACA, several states rejected the option. Over half of the national uninsured population lived in those states. The Centers for Medicare and Medicaid Services (CMS) estimated that the cost of expansion was $6,366 per person for 2015, about 49 percent above previous estimates. An estimated 9 million to 10 million people had gained Medicaid coverage, mostly low-income adults. The Kaiser Family Foundation estimated in October 2015 that 3.1 million additional people were not covered because of states that rejected the Medicaid expansion. In many states income thresholds were significantly below 133% of the poverty line. Many states did not make Medicaid available to childless adults at any income level. Because subsidies on exchange insurance plans were not available to those below the poverty line, such individuals had no new options. For example, in Kansas, where only able-bodied adults with children and with an income below 32% of the poverty line were eligible for Medicaid, those with incomes from 32% to 100% of the poverty level ($6,250 to $19,530 for a family of three) were ineligible for both Medicaid and federal subsidies to buy insurance. Absent children, able-bodied adults were not eligible for Medicaid there. Studies of the impact of Medicaid expansion rejections calculated that up to 6.4 million people would have too much income for Medicaid but not qualify for exchange subsidies. Several states argued that they could not afford the 10% contribution in 2020. Some studies suggested that rejecting the expansion would cost more due to increased spending on uncompensated emergency care that otherwise would have been partially paid for by Medicaid coverage, A 2016 study