Not sure when these were added, but I think it was recently. Just found a 14 page application for my grandfather, grandmother, aunt and uncle in 1918 (my grandmother was pregnant with my father at the time...). There was even a photo of the four of them, with letters from my great grandfathers on both sides of the family, confirming the identity and birth places of their children, a letter from my great aunt sending on yet another affadavit, etc. Apparently the boat was about to sail and their passports hadn't come through yet... Anyway, there's quite a story behind the pages, obviously.
I also found an application for one of my gg grandfathers in 1856-- good stuff!

Unfortunately, not everyone needed a passport before the 20th century, but there are a good number of old ones there nevertheless.
Cheers,
Sarah