More than 4.2 million people have signed up for private health insurance through the state and federal exchanges, Health and Human Services officials announced Tuesday. The latest statistics show the gulf between the original estimate of 7 million new customers from the Congressional Budget Office and how many people have come forward to comply with the requirement that those without insurance buy it or pay a fine. They provide mixed messages in terms of who is buying insurance and how quickly. For example, 942,000 people signed up for private plans in February, a drop from 1,146,000 in January. That's about 3,300 a day fewer in February.