If people make history, then more history is being made now than in any century before 1990. In fact, over 28% of all history made since the birth of Christ was made in the 20th century.
Source: Angus Maddison, UN, The Economist
I discovered this graph via Twitter from Alan Kohler, who is a respected, if somewhat economically dry, Australian financial journalist and business editor amongst other things. He produces the Eureka Report
Am sure you could measure history in different ways, but the graph is stark.