Are Novels Largely Autobiographical?

Are Novels Largely Autobiographical?
People who have read my fiction often make comments that assume much of what I write is autobiographical. My character's all live lives that are extremely different from the one I've been leading, but that doesn't mean my experiences didn't help me write my novels. Events, people I've known, things people have said to me, and places I have been, have frequently inspired me. For example, in "Love, Sex and Understanding the Universe," my minor character, Carol was initially modeled after a woman I once saw on a bus. I have my character seeing her on the same bus route, wearing the same outfit, but when I couldn't get a good grasp on this woman's personality, I went and borrowed the physical attributes of an acquaintance of mine in the Ozarks. Suddenly Carol came alive and she's nothing like my acquaintance except in looks.
Likewise, for years I poked around with the idea that eventually became my second novel, "Bonita Verses Ivan Rastaman and the Monkey-Go-Round," but could not get it to take a hold on me. When I had my main character say and do some things a woman once said and did with me this brought Bonnie alive, though she is extremely different from the real woman I know. Then after I went to the Rainbow Gathering here in the Ozarks I decided to put Bonnie and her father in a scene there. While she sees some of the same things I did at the Gathering, her experience is her's alone and the people she meets are fabrications based on bits and pieces of people I have come across in my lifetime. It is this scene that made the novel finally take off for me.