It was revealed on Tuesday by Sony that its PlayStation 4 console has sold over 73.6 million units as of December 31, 2017. Aside from this, over 55.9 million PlayStation 4 games were sold during the holiday period from November 20 to December 31, 2017. This is both through the PLAYSTATION Network and in physical stores.
The PlayStation 4 was first released in U.S. and Canada in November 2013 and in February 2014 in Japan. Sony expects to ship 79 million units by the end of March 31, 2018.
Source: Gematsu