Which formula is used to allocate the Hajj quota to Pakistan?

Which formula is used to allocate the Hajj quota to Pakistan?

پاکستان کو حج کوٹہ مختص کرنے کے لیے کون سا فارمولہ استعمال کیا جاتا ہے؟
Explanation

 This formula was decided during the Foreign Ministers' meeting of the Organization of Islamic Conference in 1987.