pre_text: 6. Property, Plant and Equipment Property, plant and equipment is comprised of the following: Depreciation expense on property, plant and equipment, including assets accounted for as finance leases, totaled $290.2 million in 2019, $239.6 million in 2018 and $190.4 million in 2017. The portion of depreciation expense associated with cost of providing services was 87%, 85% and 84% in 2019, 2018 and 2017, respectively. There are numerous assets included within network equipment resulting in a range of depreciable lives between 2 and 50 years, the majority of which fall within the range of 7 to 25 years No asset impairment losses were recognized in 2019, 2018 or 2017 on property, plant and equipment.
table: December 31, Depreciable
table: (dollars in millions) 2019 2018 Lives (Years)
table: Land and rights-of-way $117.2 $117.2 20 - Indefinite
table: Buildings and leasehold improvements 315.4 305.2 5 - 40
table: Network equipment 4,044.6 3,913.3 2 - 50
table: Office software, furniture, fixtures and vehicles 229.3 216.3 2-14
table: Construction in process 38.9 47.1 n/a
table: Gross value 4,745.4 4,599.1
table: Accumulated depreciation (2,964.6) (2,755.1)
table: Property, plant and equipment, net $1,780.8 $1,844.0
question: Analyse this data from a financial earnings document. What is the total network equiption between 2018 to 2019?