How many actors from the movie it's a wonderful life are still alive?

The main characters of It’s a Wonderful Life are all deceased. They include:

The protagonist, George Bailey played by screen legend James Stewart. He died in 1997.
Donna Reed (Mary Hatch) died in 1986.
Lionel Barrymore (Mr. Potter) died in 1954.
Thomas Mitchell (Uncle Billy) died in 1962.
Henry Travers (the incomparably angelic Clarence) died in 1965.

There are at least two secondary characters that are still with us as of November 2012. The actresses Virginia Patton and Karolyn Grimes portrayed Ruth Dakin Bailey and Zuzu Bailey respectively. Ruth was George Bailey’s sister-in-law, married to George’s brother Harry. Zuzu was George’s daughter. She has the legendary line, “Every time a bell rings an angel gets his wings.”

It’s a Wonderful Life was directed and co-written by Frank Capra and released in 1946.