The oldest photo I could find on Panoramio is number 15,  from 29-07-2005
The first million was reached in just over 1,5 years,  on 24-02-2007
The second million took a little more than 2 months,   on 30-04-2007
10.000.000 was reached a year later,   on 07-05-2008
Within one year we got 20.000.000,   on 13-03-2009
30.000.000, 9 months later,  on 17-12-2009
40.000.001   on 29-08-2010   =  7 months + 12 days later
50.000.000   on 25-03-2011   =  6 months + 27 days later
60.000.000   on 03-10-2011   =  6 months +   8 days later
70.000.000   on 10-04-2012   =  6 months +   7 days later
80.000.000   on 04-10-2012   =  5 months + 24 days later
90.000.000   on 08-05-2013   =  5 months +   4 days later
100.000.000 on 01-12-2013   =  6 months + 23 days later
It varies, but the difference is not terribly.
But I must admit I had expected to reach the 100.000.000 sooner.
Op woensdag 18 december 2013 19:29:14 UTC+1 schreef Erhard Bernstein: