The Printing Press
The first printing press
In 1450 there was only one printing press by 1500 there was over 200 of them (The Impact of Movable Type of Gutenberg).
The first mechanized printing press was invented by a German metalworker named Johann Gutenberg in 1452 (The Printing Press its "Impact" on Literacy).
The number of editions of the letter in the cities
Antwerp and Strasburg had one edition, Basel had two editions, Paris had three editions and Rome had four editions (Geographical Diffusion of Columbus's First Letter).
The printing press expands
The number of printing press's expand exponentially (The Impact Of Movable Type Printing Press).