Complex sentence: On opening in 1900, the library had 70,000 books and fewer than 100 manuscripts and by 2012, more than 250,000 printed volumes and over one million manuscripts and archival items.
Split into simpler sentences: On opening in 1900, the library had a stock of 70,000 books and fewer than 100 manuscripts. As of 2012, the library houses over 250,000 printed volumes and over one million manuscripts and archival items.