2000 Jimmy Tire sizes

I need a little help with the tires sizes for my Jimmy.
I have P235/70R/15 on it now. Researching different tires on the web, each mfg. comes up with P205/75R/15
I don't know which ones to get. Any advice would be great.
Thank you
Brenda

You have to put the 235-70-15

I haven't taken the time to make the calculation, but it would help to know how to read a tire size. In your post you ask about a p235/70r/15. If you break this down, the 235 is the width of the tread in millimeters. The 70 means that the sidewall is 70% of the width. The 15 means it is a 15 inch wheel. So, if you were to go with a 205 you would lose 30 millimeters of tread width (just over an inch), but since you are asking about going to a 75, it may still be pretty close to the same outer diameter.
Once you change the diameter of the tire your speedometer will be affected also.