... the 'size' of science has doubled steadily every 15 years. In a century this means a factor of 100. For every single scientific paper or for every single scientist in 1670, there were 100 in 1770, 10,000 in 1870 and 1,000,000 in 1970.
John M. Ziman (1976). The Force of Knowledge: The Scientific Dimension of Society. Cambridge University Press. p. 56-57. ISBN 0-521-09917-X.