Maturities of the principal amount of the Company’s long-term debt as of December 31, 2018 are as follows:

On or after August 1, 2018, the Company may redeem all or a portion of the Senior Notes upon not less than 30 nor more than 60 days’ notice, at the redemption prices (expressed as percentages of the principal amount) set forth below plus accrued and unpaid interest and additional interest, if any, on the Senior Notes redeemed, to the applicable redemption date, if redeemed during the twelve month period beginning on August 1 of the years indicated below:

On or after April 1, 2020, the Company may redeem all or a portion of the 6% Senior Notes due 2025 upon not less than 30 nor more than 60 days’ notice, at the redemption prices (expressed as percentages of the principal amount) set forth below plus accrued and unpaid interest and additional interest, if any, on the 6% Senior Notes due 2025 redeemed, to the applicable redemption date, if redeemed during the 12-month period beginning on April 1 of the years indicated below:

On or after September 15, 2021, the Company may redeem all or a portion of the 6% Senior Notes due 2026 upon not less than 30 nor more than 60 days’ notice, at the redemption prices (expressed as percentages of the principal amount) set forth below plus accrued and unpaid interest and additional interest, if any, on the 6% Senior Notes due 2026 redeemed, to the applicable redemption date, if redeemed during the 12-month period beginning on September 15 of the years indicated below: