To find the annual growth of the finch population, we can divide the total increase in the population by the number of years over which the increase occurred.
Given:
- Total increase in finches = 75 finches
- Time period = 3 years
We can calculate the annual increase as follows:
\[ \text{Annual Increase} = \frac{\text{Total Increase}}{\text{Number of Years}} = \frac{75 \text{ finches}}{3 \text{ years}} = 25 \text{ finches per year} \]
Thus, the finch population grew by 25 finches each year.