The AI Models Index keeps track of premium model releases from 15 top labs...

https://wiki-velo.win/index.php/What_Does_a_56%25_Improvement_Rate_Mean_for_AI_Upgrades%3F

The AI Models Index keeps track of premium model releases from 15 top labs since 2023, verifying launch dates and using blind-vote checks for accuracy. Updated biweekly, it shows that the average time between releases is now 4.5 days—a 56% improvement