The most Grand Slam winner on the male side still is Pete Sampras with:
14 titles:
2 Australian Open
0 French
7 Wimbledon
5 U.S Open titles. 
These 14 Grand Slams are taken between 1990 and 2002, 13 years of play by the American.

But on 2nd place is the the only active challenger as of today.
Roger Federer has:
12 Titles: 
3 Australian Open
0 French Open
5 Wimbledon (might be 6 today)
5 U.S Open titles.
These 12 titles are taken between 2003 and 2007, that’s only 5 years of play.

I’m a Swede so I have to review some of the Swedes.
Bjorn Borg is the best Swede ever to play Tennis, and he has been the best in the world for a long time aswell in his active years.
Here are his Grand Slam stats.
11 Titles:
0 Australian Open
6 French Open
5 Wimbledon
0 U.S Open.
These 11 titles are taken between 1974 and 1981, 8 years of play!

Second best Swede is Mats Wilander.
7 Titles:
3 Australian Open
3 French Open
0 Wimbledon
1 U.S Open
These 7 titles are taken between 1982 and 1988, 7 years of play.

Another all time favourite player, that was very popular but with a temperament was John McEnroe. According to the players he was very sportsmanlike to other players, but he got his rage attacks against the referee. But he was a champion aswell.
John got:
7 Titles:
0 Australian Open
0 French Open
3 Wimbledon
4 U.S Open
These titles was taken between 1979 and 1984, 6 years of play.

If you want more stats on Grand Slams I found these stats on Wikipedia thrue google!

I will update with the womens stats soon!