June 30,
June 30,
June 30,
($ in millions)
2019
2018
Senior unsecured notes, 5.20% due July 2021 (face value of $250.0 million at June 30, 2019 and 2018)
$251.2
$246.6
Senior unsecured notes, 4.45% due March 2023 (face value of $300.0 million at June 30, 2019 and 2018)
299.4
299.1
Total
550.6
545.7
Less: amounts due within one year
—
—
Long-term debt, net of current portion
$550.6
$545.7
10 .
debt .
on march 31 2017 the company entered into a on march 31 2017 the company entered into a $ 400 .
0 million syndicated credit facility - “ credit agreement ” that extends to march 2022 .
interest on the borrowings under the credit agreement accrue at variable rates based upon libor or a defined “ base rate ” both determined based upon the rating of the company ’ s senior unsecured long-term debt -the “ debt rating ” .
the applicable margin to be added to libor ranges from 1 .
00 % to 1 .
75 % -1 .
25 % as of june 30 2019 and for base rate-determined loans from 0 .
00 % to 0 .
75 % -0 .
25 % as of june 30 2019 .
the company also pays a quarterly commitment fee ranging from 0 .
125 % to 0 .
400 % -0 .
20 % as of june 30 2019 determined based upon the debt rating of the unused portion of the $ 400 .
0 million commitment under the credit agreement .
in addition the company must pay certain letter of credit fees ranging from 1 .
00 % to 1 .
75 % -1 .
25 % as of june 30 2019 with respect to letters of credit issued under the credit agreement .
the company has the right to voluntarily prepay and re-borrow loans and to terminate or reduce the commitments under the facility .
as of june 30 2019 the company had $ 6 .
0 million of issued letters of credit under the credit agreement and $ 19 .
7 million of short-term borrowings with the balance of $ 374 .
3 million available to the company .
as of june 30 2019 the borrowing rate for the credit agreement was 3 .
90 % .
the company is subject to certain financial and restrictive covenants under the credit agreement which among other things require the maintenance of a minimum interest coverage ratio of 3 .
50 to 1 .
00 .
the interest coverage ratio is defined in the credit agreement as for any period the ratio of consolidated earnings before interest taxes depreciation and amortization and non-cash net pension expense - “ ebitda ” to consolidated interest expense for such period .
the credit agreement also requires the company to maintain a debt to capital ratio of less than 55 percent .
the debt to capital ratio is defined in the credit agreement as the ratio of consolidated indebtedness as defined therein to consolidated capitalization as defined therein .
as of june 30 2019 the company was in compliance with all of the covenants of the credit agreement .
long-term debt outstanding as of june 30 2019 and 2018 consisted of the following : .
aggregate maturities of long-term debt for the five years subsequent to june 30 2019 are $ 0 .
0 million in fiscal years 2020 2021 $ 250 .
0 million in 2022 $ 300 .
0 million in 2023 and $ 0 .
0 million in 2024 .
for the years ended june 30 2019 2018 and 2017 interest costs totaled $ 31 .
1 million $ 31 .
1 million and $ 31 .
1 million respectively of which $ 5 .
1 million $ 2 .
8 million and $ 1 .
3 million respectively were capitalized as part of the cost of property plant equipment and software .

Question: In which years was the amount of long-term debt calculated?
Answer: 2019 2018