New York looks to be doing well in enrollment, both in raw numbers and in the mix. "Nearly 300,000 people have enrolled in the state exchange since it opened on Oct. 1st, putting the state ahead of its own projections. About one third of those who have signed up are younger than 35 years old, the so called "young invincibles" - a percentage slightly below what many experts believe is the proper mix needed for a healthy risk pool...She also said that 16 percent of enrollees are between the ages of 35 and 44." Laura Nahmias and Dan Goldberg in Capital New York.