There is an old Earth saying , a phrase of great power and wisdom and consolation to the soul in times of need- Allons-y! The 10th Doctor's catchphrase is said 19 times by David. He says it 17 times in Doctor Who, once in Dreamland and once in The Sarah Jane Adventures.
He also says Fantastic once, the 9th Doctor's catchphrase, at the end of The Christmas Invsion.
The break down:
Army of Ghosts - 7 times! This is the first time we hear it, he also says it's something he should say more often! Also he states that it would be brilliant if he met someone called Alonso so he could say Allons-y Alonso!
Evolution of the Daleks - one
42 - one
Voyage of the Damned - twice - including the Allons-y Alonso - something he always wanted to say!
The Fires of Pompeii - Nice bit of Allons-y! - said after a good run!
Midnight - He says it twice and Sky says it once - also the only episode that he translates the French
The Next Doctor - said with David Morrissey in unison
Planet of the Dead - said to Lady Christina
The End of Time, Part Two - The quote at the beginning of the blog.