Professor Snape took five points from Gryffindor house because he claimed that library books were not to be taken outside the school after he found Harry reading Quidditch Through the Ages in the grounds. Harry, Ron and Hermione were sure he had made that rule up on the spot.
Severus Snape took many points away from Gryffindor throughout the years. He Favorited Slytherin house and had a grudge against Harry's father, so took it out on Harry.
Harry Potter lost one point for being cheeky to Severus Snape and another because Snape blamed him for Neville Longbottom melting his cauldron (although it had nothing to do with Harry).
Ten. They were tied and then Professor Dumbledore awarded Neville ten points for standing up to his friends.
In the 1991-1992 school year (Harry Potter's first year) they won by 10 points with a total of 482 points. None of the other books state what the total number of points were. It is known that Gryffindor won the 1992-1993 and 1993-1994 house cup. The winners for rest of the years are unknown.
426. Ravenclaw finished in third place, after Slytherin.
Nothing, Draco laughs at him as Severus Snape shoots scathing remarks at Harry and removes points from Gryffindor.
Severus Snape took many points away from Gryffindor throughout the years. He Favorited Slytherin house and had a grudge against Harry's father, so took it out on Harry.
Harry Potter lost one point for being cheeky to Severus Snape and another because Snape blamed him for Neville Longbottom melting his cauldron (although it had nothing to do with Harry).
Harry caught the Snitch after Gryffindor scored 80 points.
Ten. They were tied and then Professor Dumbledore awarded Neville ten points for standing up to his friends.
The first match of the year, Gryffindor versus Slytherin, ended with 170 points to 60. The scores for the other matches are unknown, although Gryffindor beat Hufflepuff but lost to Ravenclaw.
In the 1991-1992 school year (Harry Potter's first year) they won by 10 points with a total of 482 points. None of the other books state what the total number of points were. It is known that Gryffindor won the 1992-1993 and 1993-1994 house cup. The winners for rest of the years are unknown.
In Philosopher's Stone, Hermione mentions that she heard Dumbledore was in Gryffindor. It was also confirmed in the Pottermore welcome video for students sorted into Gryffindor House.
426. Ravenclaw finished in third place, after Slytherin.
In the Quidditch match, Slytherin is ahead by 200 points. So Harry being the Seeker, must only catch the Snitch when Gryffindor is ahead by 80 points or more, because if Harry catches the Snitch, the game ends, and they get 150 points, which would put them below Slytherin for the Quidditch Cup.
Neville Longbottom was awarded ten house points at the end of Harry Potter and the Philosopher's Stone. Dumbledore gave him the points because he managed to stand up to his friends, which is harder than standing up to your enemies.
In the 1993-1994 school year (Harry Potter's third year) Gryffindor won the house cup but it is unknown how many points they gained. In the 1994-1995 school year (Harry Potter's fourth year) it is unknown what house won the cup and how many points each house gained. It is possible that the cup wasn't awarded due to Cedric Diggory's death.