Or three, depending on which Google search you choose to use.Depends how far you want to back.
If you average it out at 5 every 50 years it's a few if you get down to the 17th century
Then you'd have to look at Global trends rather than just averaging out the numbers and peer into the dusty archives where geologists keep their rock samples to check on how much rainfall there was for a certain region. You're still hooked up on weather patterns for observing Climate Change.