Years Ended December 31, | |||||||||||||||||||
2017 | 2016 | 2015 | 2014 | 2013 | |||||||||||||||
Earnings: | |||||||||||||||||||
Income before income tax expense | $ | 100,544 | $ | 75,491 | $ | 70,307 | $ | 84,710 | $ | 67,723 | |||||||||
Fixed charges interest expense | 36,570 | 33,748 | 29,467 | 28,765 | 31,179 | ||||||||||||||
Allowance for funds used during construction | (6,110 | ) | (2,965 | ) | (1,915 | ) | (1,535 | ) | (2,038 | ) | |||||||||
Total | 131,004 | 106,274 | 97,859 | 111,940 | 96,864 | ||||||||||||||
Fixed Charges: | |||||||||||||||||||
Interest expensed & capitalized, & amortization of capitalized expense related to indebtedness | 36,288 | 33,466 | 29,185 | 28,483 | 30,897 | ||||||||||||||
Estimated interest component of rent expense | $ | 282 | $ | 282 | $ | 282 | $ | 282 | $ | 282 | |||||||||
Total | 36,570 | 33,748 | 29,467 | 28,765 | 31,179 | ||||||||||||||
Ratio of earnings to fixed charges | 3.58 | 3.15 | 3.32 | 3.89 | 3.11 |