From 2016: "THE LOC’S DIGITAL COLLECTION currently comprises over 7 petabytes (7 million gigs) with more than 15 million items, including 150,000 print books. In an ideal future scenario, the LOC estimates that it could digitize a further 3-5 PB a year" [1]

So only the raw texts, probably. 10TB sounds about right for that.

[1] https://nplusonemag.com/online-only/online-only/the-library-...