pre_text: Free cash flow generation Bridge from operating income to free cash flow (illustrative) Focus on delivering a high conversion of operating income to free cash flow of operating income to free cash flow
  of operating income to free cash flow Ongoing activities to reduce costs “below operating income”, including restructuring, financial net and tax Striving to maintain working capital efficiency but fluctuations may impact cash flow Planning assumption for capex is about 2% of net sales, while expected to remain above 2% in 2020 due to the new factory in the US Ambition to over time maintain restructuring charges to around 1% of net sales M&A will vary depending on strategic decisions but assumed to be around 1–2% of net sales Operating margin excluding restructuring charges. All numbers are in relation to net sales. 1) Restructuring charges as reported in the income statement for each year.
table: 2018 2019 Ambition
table: Operating margin 4.4% 5.0% >12%
table: financial net, tax and other -3.8% -2.5% -4%
table: + depreciation and amortization +3.9% +2.9% +3 to 4%
table: + depreciation of leased assets – +1.1% +1%
table: ± change in working capital +3.7% +1.0% ±0
table: - capex - 2.4% -2.8% -2%
table: - leasing payment - -1.3% -1%
table: -  restructuring costs1) -3.8% -0.4% -1%
table: Free cash flow (before M&A) 2.0% 3.4% >8%
table: - M&A -0.6% -0.7% ~1 to -2%
question: Analyse this data from a financial earnings document. What is the change in capex between 2018 and 2019?