Since only the first value changes, and its weight doesn't, that's relatively simple to calculate.

The first values give, as you say, a weighted average of (4*10+8*15+19*31+....+72*100)/(10+15+31+....+100)= (40+ 8547)/199= 8587/199= 43.2 (toonedecimal place- it is 43.15 totwodecimal places). If the "4" increases to 6 we have (60+ 8547)/199= 8607/199= 43.26 to two decimal places. In terms of percentages, the second number is or 103%