Most open enrollment for the Affordable Care Act ends Sunday. 
A record 16 million people have signed up since November. More than three million of them are new sign-ups.  
The government says the Affordable Care Act is gaining popularity after federal enhancements reduced the price.  
Most people can find plans that cost less than $10 a month. 
Even after open enrollment ends, Americans who lose health care or have very low income can still sign up throughout the year.