Caveat: Part of these effects could be due to the banning of bots in August 2019 which of course is a good thing.
I took the August 2018 and 2019 data from the MERs and did a comparison by NS region.
The overall reduction in ratting/mining income: ~68%.*
In August 2018 the combined ratting/mining income was ~95.2 trillion ISK.
In August 2019 the combined ratting/mining income was ~30.3 trillion ISK.
Total reduction from 2018 to 2019 August ratting/mining income was ~65 trillion ISK.
*Note this is also the weighted average of the regional reduction as well.
Here are the top 10 most affected regions
Since everyone focuses on Goons:
Delve ranked 26th in terms of reduction in ISK/minute going from ~414 million ISK/minute to ~180 million ISK/minute.
Delve still ranks as number one in terms of ISK/minute followed again by Esoteria (with ISK/minute statistics of ~159 million ISK/minute and ~56 million ISK/minute respectively).
Some regions did see an increase in their ISK/minute but these regions were already very low in ISK/minute anyways so even a moderate increase in ratting/mining could have caused a substantial increase. For example, Omist saw the ISK/minute nearly trip from ~7.2 million to ~20.3 million ISK.