Americans are living longer, thanks to medical breakthroughs and better living.

According to U.S. Census Bureau projections, 1 in 5 Americans will be 65 or older, and at least 400,000 will be 100 or older.

And some futurists predict many Americans will be able to live to be at least 120 years old thanks to new medical treatments that could slow or stop the aging process altogether.

But a Pew Research poll says, most Americans wouldn't want to live decades longer.

Would you want to live to be 120?