The bear population is proportionally related to the number of years because the ratios are equivalent. This can be seen by calculating the ratio of bear population to years for each row:
1st row: 6/1 = 6
2nd row: 120/20 = 6
3rd row: 240/60 = 4
Since the ratios are all equal (6), it can be concluded that the bear population is proportionally related to the number of years.