By Katie Kerwin McCrimmon Sen. Irene Aguilar, D-Denver, plans to introduce a bill on Friday seeking universal health care in Colorado. Under her plan, employers would pay a 6 percent payroll tax for each worker while employees would pay a 3 percent share. Self-employed people and investors would pay a 9 percent tax on income and capital gains. In exchange for those costs, all Coloradans who have lived in the state for at least one year by the beginning of 2016 would become part of a statewide health care co-op and would get platinum-level health plans, the most generous package…