How many followers of sufism?

Millions. mainly Suni Muslims and Shia Muslims and others that believe only in one brotherhood and do not believe to be a part of any sect also sufism is followed by many Siks, Hindus and other religions . only Kharji or they are known as Wahabi dont follow the concepts of sufism.

Its a open believe that God makes friends in this world and loves them and love those who love his friends.

Mubashir Shah