Sony’s PlayStation 4 has been a consistently high performer, taking the crown as the best selling console of this generation thus far. However, in a recent earnings report, Sony has revealed that sales for the console are beginning to slow, with numbers down year-on-year. For the 2017 Christmas period, Sony revealed that it sold 9 million PS4 consoles, which is down slightly on the 9.7 million sold across the same period the previous year.