https://www.nytimes.com/1992/02/11/us/the-1992-campaign-iowa-harkin-dominates-state-s-caucuses.html

Another interesting note from the 1992 election cycle included major Democratic candidates ceding the Iowa caucuses to Iowa Senator Tom Harkin (who was the presumed frontrunner in the state, and ended up winning all 49 of Iowa’s pledged delegates).  I would imagine this withdrawal from the Iowa caucuses was highly unusual for the time period.  Considering that Iowa must conduct the first caucus of the primary season, according to its own state constitution, I wonder if public perception diluted the value placed on the Iowa caucus in this election cycle.

A chart of the 1992 Democratic primary election results can be found here: https://en.wikipedia.org/wiki/1992_Democratic_Party_presidential_primaries