pre_text: The difference between the tax provision at the statutory federal income tax rate and the tax provision as a percentage of income before income taxes (effective tax rate) for each period was as follows: The majority of the increase in our effective tax rate in 2019 compared to 2018 was driven by one-time benefits that occurred in 2018. The majority of the decrease in our effective tax rate in 2018 compared to 2017 resulted from initial tax expense from Tax Reform and the tax impacts from the ISecG divestiture that we had in 2017, but not in 2018. The reduction of the U.S. statutory rate, combined with the net impact of the enactment or repeal of specific tax law provisions through Tax Reform, drove the remaining decrease in our effective tax rate in 2018. We derive the effective tax rate benefit attributed to non-U.S. income taxed at different rates primarily from our operations in China, Hong Kong, Ireland, and Israel. The statutory tax rates in these jurisdictions range from 12.5% to 25.0%. In addition, we are subject to reduced tax rates in China and Israel as long as we conduct certain eligible activities and make certain capital investments. These conditional reduced tax rates expire at various dates through 2026 and we expect to apply for renewals upon expiration.
table: Years Ended Dec 28, 2019 Dec 29, 2018 Dec 30, 2017
table: Statutory federal income tax rate 21.0% 21.0% 35.0%
table: Increase (reduction) in rate resulting from:
table: Non-U.S. income taxed at different rates (3.7) (3.6) (7.6)
table: Research and development tax credits (2.3) (2.7) (2.3)
table: Domestic manufacturing deduction benefit — — (1.3)
table: Foreign derived intangible income benefit (3.2) (3.7) —
table: Tax Reform — (1.3) 26.8
table: ISecG divestiture — — 3.3
table: Other 0.7 (0.1) (1.1)
table: Effective tax rate 12.5% 9.7% 52.8%
question: Analyse this data from a financial earnings document. What is the average effective tax rate from 2017 to 2019?