pre_text: 2019 vs 2018 SMB segment net revenue was flat for the year ended December 31, 2019 compared to the prior year, primarily due to a decline in net revenue of our
  network storage products, substantially offset by growth in net revenue of our switch products. Geographically, net revenue grew in APAC, but declined in Americas and EMEA. Contribution income decreased for the year ended December 31, 2019 compared to the prior year, primarily as a result of lower gross margin attainment, partially offset by lower operating expenses as a proportion of net revenue. Contribution margin decreased for the year ended December 31, 2019 compared to the prior year, primarily lower gross margin attainment mainly resulting from foreign exchange headwinds due to the strengthening of the U.S. dollar as well as higher provisions for sales returns. 2018 vs 2017 SMB segment net revenue increased for the year ended December 31, 2018 compared to the prior year, primarily due to growth in switches, partially offset by the decrease in network storage. SMB experienced growth in net revenue across all regions. SMB net revenue was further benefited by lower provisions for sales returns deemed to be a reduction of net revenue. Contribution income increased for the year ended December 31, 2018 compared to the prior year, primarily due to increasing net revenue and improved gross margin performance not being met with proportionate increases in operating expense compared to the prior period.
table: Year Ended December 31,
table: 2019 % Change 2018 % Change 2017
table: (in thousands, except percentage data)
table: Net revenue $287,372 (0.1)% $287,756 6.2% $270,908
table: Percentage of net revenue 28.8% 27.2% 26.1%
table: Contribution income $67,282 (4.1)% $70,142 9.8% $63,865
table: Contribution margin 23.4% 24.4% 23.6%
question: Analyse this data from a financial earnings document. What was the change in contribution income from 2017 to 2018?