pre_text: 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.
table: December 31, 2019 Gross Cost Accumulated Amortization Net Cost
table: Technologies & licenses 699 (578) 121
table: Purchased & internally developed software 486 (427) 59
table: Technologies in progress 119 — 119
table: Other intangible assets 70 (70) —
table: Total 1,374 (1,075) 299
table: December 31, 2018 Gross Cost Accumulated Amortization Net Cost
table: Technologies & licenses 705 (592) 113
table: Purchased & internally developed software 459 (404) 55
table: Technologies in progress 44 — 44
table: Other intangible assets 69 (69) —
table: Total 1,277 (1,065) 212
question: Analyse this data from a financial earnings document. What is the average Accumulated Amortization?