Here's the chart, which seems to prove what we've suspected - sci fi is taking a nose dive since the heydays of the mid to late 90s.
The chart could be misleading, however, since it tracks numbers of themes rather than numbers of shows. Maybe what we're seeing is single-theme sci fi. Heroes = mutants/aliens, Lost = time-travel, Terminator = robots but Star Trek used to have em all in just one episode...
PS, the chart to the left only lists some of the shows they surveyed, so don't fret if you don't see Supernatural or Lost. The whole list is here.
The chart could be misleading, however, since it tracks numbers of themes rather than numbers of shows. Maybe what we're seeing is single-theme sci fi. Heroes = mutants/aliens, Lost = time-travel, Terminator = robots but Star Trek used to have em all in just one episode...
PS, the chart to the left only lists some of the shows they surveyed, so don't fret if you don't see Supernatural or Lost. The whole list is here.