I can answer too, but watching extensively Tv series is not my only way of trying to progress.
So, my self-estimated passive level is a good B2 in russian (my productive level is rather B1).
I've watched extensively 38 series: humor:10, detective:9, melodrama/drama:9, teens-geared (for slang):2, aventure:1, criminal/war:1, cartoon:1, lawers:1, sci-fi:1, other:the remaining.
Total calculated, for the time being: 463 hours. (usually one episode of a humor series last 25 minutes, and the other between 40 and 50 minutes). Several series have been watched twice or thrice over the years to measure the progresses and to reactivate the known material.
On the 38 series, 9 have been watched with russian subtitles or transcripts, 2 with english subtitles (I'm french, but finding russian series subtitled in french is impossible: I know only two series partially subtitled in french but I didn't watch them because I wasn't interested by the plot). These 9 series have been or will be watched also intensively, looking for all the unknow words in the dictionary, by little chunks of 10/15 minutes (10/15 correspond to 1 hour of work: listening once, reading the text, looking for the unknown words, noting the unknown words in a notebook, listening again several time until what I hear is clear enough and that I understand everything: it's very time-consuming and I don't count that in the 463 hour I mentionned.). The remaining has been watched without subtitles.
Some have been watched with lot of attention, other in the background or during lunch-time or in the evening while doing other things (so not very seriously, just to have a russian audio background).
Now, I'm watching less series and concentrate more on radio, podcasts, reading and audiobooks. On the whole, I think I have progressed by watching Tv series, but not by "leaps and bounds" as other people often say. It's a slow and "painful" progress, in my case (perhaps not enough repetition: Perhaps I should have watch again the same series more often, perhaps I'll do that in the future...my method to learn languages is not very elaborated, it's more a constant "trial and error" process)
That's all folks, thanks for reading