10,well,some are just brought back to earth.I can't remember how all of them left,but most were just taken back home.
10, that sounds like a challenge to me
Susan left to get Married I'm pretty sure
from what I gather Ian and Barbara left of their own accord (and we pretend that they got married
)
don't know about Stephen or Dodo
Sarah Kingdom is in there somewhere and she died
Ben and Polly left of their own accord at the same time (and we pretend they got married too
)
Victoria left by her own choice (I listened to that episode, really cute)
Jamie and Zoe had their memories wiped and were put back where they came from
I guess Liz and Jo left on their own too
Sarah Jane accidentally got left behind
Harry chose to leave
Leela... I know she ended up on Gallifrey somehow...
don't know about Romana
Adric Died
Nyssa left to help out at the space station Terminus
Tegan finally left on her own after wanting to for a long time *rolls eyes*
Turlough left because his planet thought his whole family were convicted criminals, not to mention he had to help his people who were left on that planet as the volcano was exploding...
Don't know about Mel, Peri or Ace
Grace stayed on her own, and she asked the Doctor to stay with her but he didn't want to
Rose *does not do spoilers*
Martha left to save the world
Donna *does not do spoilers*