Auction values for the publishing rights to Collected Works of William Shakespeare:
1709: "a small fraction of" 200 pounds
1734: "less than" 675 pounds
1741: 1,630 pounds
1765: 3,462 pounds
1774, End of perpetual monopoly copyright: Nil
That is from William St. Clair’s recent The Reading Nation in the Romantic Period. Many books deal with the rise of print culture and the commercial revolution, but in terms of thoroughness and data work, this marvelous work is a clear number one. Here is more on the book. I am learning just how much early British copyright law kept the price of literature high, and kept books out of public hands.