OK, here's an English football trivia question I've come up with. I'm interested to see if anyone knows the answer.

In the 1991-92 season there were 11 clubs who had done this.
From 1992 to 1995 there were 8.
From 1995 to 1996 there were 7.
From 1996 to 2002 there were 6.
From 2002 to 2003 there were 5.
From the start of next season there'll be 4.
Who are they and what have they done?

If you're completely stuck, this site might help you find the answer.