The amount of actual value added which is eligible to be exempt from taxation shall be as follows:
(Code of Iowa, Sec. 427B.3)
1. For the first year, seventy-five percent (75%)
2. For the second year, sixty percent (60%)
3. For the third year, forty-five percent (45%)
4. For the fourth year, thirty percent (30%)
5. For the fifth year, fifteen percent (15%)