This is determined by cointing the teath on the ring gear and deviding them by the pinion gear. Another way is to jack up one tire and count the rotations of the driveshaft when rotated 2 times.
The R&P Ratio on a '92 Suzuki Sidekick 1.6L depends on the transmission type: Automatic= 4.62 Manual=5.12 **See Related Links for Suzuki Manuals on Google Docs