pre_text: For purposes of reconciling the Company’s provision for income taxes at the statutory rate and the Company’s provision (benefit) for income taxes at the effective tax rate, a notional 26% tax rate was applied as follows (in thousands): The difference between the statutory federal income tax rate and the Company’s effective tax rate in 2019, 2018 and 2017 is primarily attributable to the effect of state income taxes, difference between the U.S. and foreign tax rates, deferred tax state rate adjustment, share-based compensation, true up of deferred taxes, other non-deductible permanent items, and change in valuation allowance. In addition, the Company’s foreign subsidiaries are subject to varied applicable statutory income tax rates for the periods presented.
table: Year Ended December 31,
table: 2019 2018 2017
table: Income tax at federal statutory rate $(10,883) $(9,811) $(6,659)
table: Increase (decrease) in tax resulting from:
table: State income tax expense, net of federal tax effect (3,657) (2,749) (421)
table: Nondeductible permanent items 3,522 (1,522) 1,506
table: Foreign rate differential (367) 552 599
table: Tax rate change — 134 7,226
table: Adjustment to deferred taxes (1,904) 307 37
table: Change in valuation allowance 22,481 15,805 (2,291)
table: Uncertain tax positions 128 143 76
table: Nonqualified stock option and performance award windfall upon exercise (9,128) (1,983) —
table: Other 233 (80) (26)
table: Total $425 $796 $47
question: Analyse this data from a financial earnings document. What is the average Nondeductible permanent items from 2017-2019?