population forecast

Do you know the formula you want to use?

yes, Geometrical Increase method

Pn = Po[1 + (r/100)]^n,

where,

Po - last known population,

Pn - population (predicted) after 'n' number of decades,

n - number of decades between Po and Pn and,

r - growth rate = (increase in population/initial population) * 100 (%).

Do you have enough data for previous years to calculate a value for r? Can you share a screenshot of what your data looks like?

yes