During the 1990’s, I started collecting Lego catalogs. These would be given for free at the toy section of SM malls. I have square catalogs from 1995 to 1999.
The 1995, 1997, and 1998 catalogs have 32 pages each; the 1996 catalog has 36 pages; and the 1999 catalog has 48 pages.
I also have a few smaller rectangular ones. The 1994 catalog below has 32 pages and covers the Duplo (0-6 years old), the Lego System (3-16 years old), and the Lego Technic (7-16 years old) units.
The rectangular 1996 Lego Systems catalog below has 24 pages. It doesn’t include any pages on the Duplo series which occupied 10 pages in the square 1996 catalog.