based on the number of characters , total of 10 000 characters, so each character is 0.01 percent. (10000 = 100%) maybe for bigger publications a larger number of total characters
Monospaced font, maybe more info to show up on mouse rollover or something
easy to program yet an typographic approach unlike anything thats on the visible data website right now
kinda reminds me of http://www.joodsmonument.nl/