Table:
| December 31, 2019 | Gross Cost | Accumulated Amortization | Net Cost |
| --- | --- | --- | --- |
| Technologies & licenses | 699 | (578) | 121 |
| Purchased & internally developed software | 486 | (427) | 59 |
| Technologies in progress | 119 | — | 119 |
| Other intangible assets | 70 | (70) | — |
| Total | 1,374 | (1,075) | 299 |
| December 31, 2018 | Gross Cost | Accumulated Amortization | Net Cost |
| Technologies & licenses | 705 | (592) | 113 |
| Purchased & internally developed software | 459 | (404) | 55 |
| Technologies in progress | 44 | — | 44 |
| Other intangible assets | 69 | (69) | — |
| Total | 1,277 | (1,065) | 212 |
Paragraphs:
As described in Note 7, the acquisition of Norstel resulted in the recognition of technology in process for $86 million in the line “Technologies in progress”.
The line “Technologies in progress” in the table above also includes internally developed software under construction and software not ready for use.
The amortization expense in 2019, 2018 and 2017 was $69 million, $64 million and $58 million, respectively.
Question:
What is the average Accumulated Amortization?
Answer: (1075+1065) / 2 = 1070