23, to be exact. 4, 5, 6 and 7 can be used as bases.
14x Hornblower (spoilers for Retribution)
8x Firefly (spoilers for... nothing much, it won't make sense if you haven't seen the episode so not really a spoiler. Firefly is great in that you can generally rely on people to have seen the whole thing!)
1x Song Lyrics
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