109% increased by 15% over 8 years
To calculate the total percentage increase, we first find the increase over 8 years:
109% increased by 15% = 109% + (109% * 15%) = 109% + 16.35% = 125.35%
So, the total increase over 8 years is 125.35%.
Therefore, the value has increased by 125.35% over 8 years.