Passage

Given below is the data about students appeared in two exams i.e., A and B in six different years i.e., 2011 to 2016. Total students appeared in both exam in 2016 is 8000 while in 2013 it is 5800. Average number of students appeared in exam B in 2011 and 2013 is 3100 and is in the ratio 18 : 13. Students appeared in exam A in year 2015 is 100/3% more than students appeared in exam B in same year. Total students appeared in 2016 is 25% more than total students appeared in 2011. Students appeared in exam A in 2016 is 62(26/27) % more than students appeared in exam B is 2015. Ratio of total students appeared in 2016 & 2014 is 16 : 13. Total number of students appeared in exam A in all six years is 21,100. Students appeared in exam B in 2011 is same as student appeared in exam A in 2015.Students appeared in exam A in 2012 is 700 more than that of students appeared in same exam in 2014. Students appeared in exam B in 2014 is 1200 less than that of in same exam in 2012

Find the difference between average number of students appeared in exam A and average of students appeared in exam B in starting four years?