Looks like CTAS had 5 stock splits over the years (see below), so the $3 for 1990 would be a split adjusted figure. Sure wish I'd stuck with conservative growth stocks like CTAS over the years, instead of crazy sectors like biotech..
>>> Stock split history for Cintas (CTAS)
Cintas stock (symbol: CTAS) underwent a total of 5 stock splits.
The most recent stock split occured on March 8th, 2000.
One CTAS share bought prior to April 3rd, 1987 would equal to 18 CTAS shares today.