Derek, a cash basis, unmarried taxpayer, had $2,100 of state income tax withheld during 2018. Also in 2018, Derek paid $210 that was due when he filed his 2017 state income tax return and made estimated payments of $4,200 towards his 2018 state income tax liability. When Derek files his 2018 Federal income tax return in April 2019, he elects to take the standard deduction, which reduced his taxable income. As a result of overpaying his 2018 state income tax, Derek receives a refund of $1,470 in 2019.

How much of the $1,470 will Derek include in his 2019 gross income?