Instead of a single number, you need to consult your vehicle's repair manual. This manual will detail the proper fuel pressure testing procedure and specify acceptable ranges, not just a single "correct" pressure.
You'll need to perform a pressure test using a fuel pressure gauge designed for this purpose. This test usually involves connecting the gauge to the fuel system's test port. The repair manual will guide you through this process safely. Improper handling of fuel systems can be dangerous.
In short: Don't rely on a single pressure figure from the internet. Use your vehicle's repair manual for accurate specifications and testing procedures.