CosmicSex on 20 September 2014
Both have been out for approximately 10 months.
Sony is averaging 1.1 million a month
Microsoft is averaging .54 million a month.
20=1.1x (x = months)
x=18.18 months to reach 20 million
10=.54x
x=18.54 months to reach 10 million
Of course there are giant caveats to this but PS4 and Xbox One should reach 20 million and 10 million respectively around the same month.
