How many Tm drops are in which kind of raids?

Absol & Tyranitar are now soloable as tier 4's, with maxed out Counter/Dynamic Punch Machamps. Weather boosted cloudy weather for Big T. TM's more frequent from tier 4/5's but do drop occasionally at tier 3.

My rough estimate for tier 3 raid TMs would be about 1 for every 3 raids. Maybe that's a little too optimistic - not less than 1 in 5. It does go in streaks though.

https://thesilphroad.com/science/raid-reward-odds-april-2018/

Rewards come in a number of bundles based on the number of premier balls you earn for personal damage contribution, team contribution, and gym control (not friendship). TMs have higher chances in T3+, and you can get more bundles which provide more tries.

With the probabilities presented in the SilphRoad research, a T3 solo raid should on average drop fast TMs about 1 in 5 raids and charge TMs about 1 in 10 raids.