pre_text: The following table summarizes the change in the valuation allowance (in thousands): As of December 31, 2019, net operating loss (NOL) carryforwards for U.S. federal tax purposes totaled $31.4 million. Effective with the 2017 Tax Act in December 2017, NOLs generated after December 31, 2017, do not expire. Federal NOLs of $9.9 million expire at various dates from 2020 through 2037 and federal NOLs of $21.5 million do not expire. NOL carryforwards for state tax purposes totaled $40.6 million at December 31, 2019 and expire at various dates from 2020 through 2039.
table: Year Ended December 31
table: 2019 2018
table: Vaulation allowances, beginning of year $5,398 $13,872
table: Net operating loss 3,284 1,920
table: Expiration of net operating losses and limitations (7) (9,939)
table: Adjustment to deferred taxes 29 (321)
table: Impact of state tax rate change 26 (146)
table: Other adjusments 9 12
table: Valuation allowance, end of year $8,739 $5,398
question: Analyse this data from a financial earnings document. What is the change in valuation allowance in 2018?