What was a typical UV index 10-20 years ago?

Question

Today where I live its 9. Is this higher than it would've been 20 years ago (average)?

Answer 1

The UV is reflective of the total amount of UV radiation reaching the surface of the earth.  It varies day to day based on cloud cover and the angle of the sun in the sky.  Other long-term factors can come into play such as the amount of ozone in the earth's stratosphere.  All other factors have vary little impact on the amount of UV radiation that reaches the surface.  20 years ago, you can assume all the above factors were about the same, which means that on average, the UV index was probably the same as it is today.

Answer 2

It would probably be lower now, and higher 20 years ago.