Connecticut has opened enrollment in the state's Charter Oak health plan. The plan is open to those who don't qualify for existing state programs and aren't insured through an employer. Individual premiums will range from $75 a month to as high as $259 a month. The state expects to serve a projected 19,200 adults during the first year, rising to 47,200 in its third year. The state is contracting with three private insurers to coordinate benefits and medical providers.