I am doing a time-series data analysis. The idea is to produce a forecast from the regression output. I am regressing Air traffic passengers of country A with GDP/capita of country A.
I am getting very high R² (0,97) by regressing absolute values of Air traffic passengers of country A with GDP/capita of country A (p.value<0,05)
I am getting low R²(0,35) by regressing the same variables but that time, by taking the %growth of those variables. (p.value<0,05)
What is the most accurate in this case? regress absolute values or regress the %growth?