With reference to her reply to question 2463 on 5 September 2017 regarding the amount of debt owed to the National Student Financial Aid Scheme (NSFAS) by graduates, (a) what is the total number of graduates whose debt adds up to R6.148 billion, (b) what proportion of the debt owed by graduates has been repayable for (i) less than three years and (ii) more than three years, (c) what amount of debt owed by the graduates has been (i) prescribed and (ii) written off and (d) whether each amount has been included in the total amount owed to NSFAS by graduates?