pre_text: Other intangible assets were comprised of: Amortization expense of other intangible assets was $364.7, $316.5, and $294.3 during the years ended December 31, 2019, 2018 and 2017, respectively. Amortization expense is expected to be $400 in 2020, $383 in 2021, $379 in 2022, $347 in 2023 and $321 in 2024.
table: Cost Accum. amort. Net book value
table: Assets subject to amortization:
table: Customer related intangibles $3,926.8 $(1,083.6) $  2,843.2
table: Unpatented technology 504.0 (199.5) 304.5
table: Software 172.0 (93.2) 78.8
table: Patents and other protective rights 9.7 (7.5) 2.2
table: Trade names 7.3 (2.8) 4.5
table: Assets not subject to amortization:
table: Trade names 608.9 — 608.9
table: Balances at December 31, 2018 $  5,228.7 $(1,386.6) $  3,842.1
table: Assets subject to amortization:
table: Customer related intangibles $  4,955.4 $(1,349.4) $  3,606.0
table: Unpatented technology 613.0 (279.6) 333.4
table: Software 172.2 (111.5) 60.7
table: Patents and other protective rights 12.0 (8.0) 4.0
table: Trade names 7.9 (4.1) 3.8
table: Assets not subject to amortization:
table: Trade names 659.8 — 659.8
table: Balances at December 31, 2019 $ 6,420.3 $(1,752.6) $ 4,667.7
question: Analyse this data from a financial earnings document. What is the proportion of the cost of software and trade names over total cost in 2018?