When did provisionals start?

Some good info coming from Jayski.

Provisionals Stay in 2002: NASCAR president Mike Helton said in a chat on NASCAR.com this week that the series wouldn't change its provisional system for next year. The final seven starting spots each weekend are provisionals. Helton: It is a program designed to help someone who competes every week, but is having a bad week. The evolution of that process is that we have 7 provisionals in a 43-car field. We will keep looking at it and tweaking it, but we will not change anything for the 2002 season. (11-17-2001)
Some Facts: from below: #24-Jeff Gordon has never used a provisional in his Winston Cup career, he started 40th at Talladega in 1994 when there were only two provisional spots, 41 and 42. And in Nov 1997, Gordon started 37th at Atlanta but then NASCAR only used four (plus a champs) provisional. AND:
how provisionals have progressed over the past few years:
before 1994 not sure how it was handled
1994 - two
1995 - four
1996 - four plus 1 champs(if no champ used it, it went unused)
1997 - four plus 1 champs(if no champ used it, the next team in owners points got it)
1998 - six plus 1 champs(if no champ used it, the next team in owners points got it)
1999 - six plus 1 champs(if no champ used it, the next team in owners points got it)
2000 - six plus 1 champs(if no champ used it, the next team in owners points got it)
2001 - six plus 1 champs(if no champ used it, the next team in owners points got it)(11-18-2001)

www.jayski.com/stats/2001/2001prov.htm

I believe it started between 1988 and 1991. Remember that Richard Petty had 4 DNQs in 1989, and then hadn't more, despite not having a competitive car and no longer being a competitive driver.