Table:
| FOR THE YEAR ENDED DECEMBER 31 | 2019 | 2018 |
| --- | --- | --- |
| Interest expense on long-term debt | (1,024) | (918) |
| Interest expense on other debt | (153) | (133) |
| Capitalized interest | 45 | 51 |
| Total interest expense | (1,132) | (1,000) |
Paragraphs:
Note 6 Interest expense
Included in interest expense on long-term debt is interest on lease liabilities of $220 million for 2019 and interest on finance leases of $142 million for 2018.
Capitalized interest was calculated using an average rate of 3.96% and 3.88% for 2019 and 2018, respectively, which represents the weighted average interest rate on our outstanding long-term debt.
Question:
What was the average rate used to calculate capitalized interest in 2018?