Let me explain
"Approximately half" of PS4 owners are subscribed to PlayStation Plus, Sony head Kaz Hirai said in an investors meeting.
If you will allow me to do some maths. Sony has sold over seven million (7) PlayStation Fours (4s). Installing seven (7) in the position of "numerator" atop a dividing line, we can then install two (2) into the position of "divisor." Executing this function, you will come to the conclusion that around three point five (3.5) million PS4 owners have purchased membership into the cult of PS+.