system
A chat on subreddit /r/me_irl
human
Series 1-7 all had 13 episodes each

Series 8-10 had 12 episodes each

Series 11 and 12 both had 10 episodes

Series 13 only had 6 episodes because Covid
gpt
series 13 had 9 episodes bcz of eve of the daleks legend of the sea devils and the power of the doctor