In the last 3 years, total export earnings = (18.5 + 22 + 24.5) = 65 billion dollar
In the last 3 years, total import earnings = (22+ 23.5 + 27.5) = 73 billion dollar
∴ In the last three years, the total export earnings is $\dfrac{65}{73}$ percents = 89.04% ≅ 89% of the value of the imports.