[eigen]

2015 Sky Lake i5-6600K single core 1092 [1]

2017 Kaby Lake i5-7600k single core 1157 [2]

2017 Coffee Lake i5-8600k single core 1206 [3]

2018 Coffee Lake i5-9600k single core 1233 [4]

2020 Comet Lake i5-10600k single core 1307 [5]

16% improvement over 5 years, average 4.6% improvement per release, range from 2.2% to 6% per step. didn't realize that they released 2 Coffee Lakes.

[1] https://browser.geekbench.com/processors/intel-core-i5-6600k

[2] https://browser.geekbench.com/processors/intel-core-i5-7600k

[3] https://browser.geekbench.com/processors/intel-core-i5-8600k

[4] https://browser.geekbench.com/processors/intel-core-i5-9600k

[5] https://browser.geekbench.com/processors/intel-core-i5-10600...

[formerly_proven]

Those are all Skylake CPUs with very minor tweaks. The biggest change being clock frequencies steadily increasing due to 14 nm evolving into the ultra-mature 14+++ nm process.