pre_text: 10. Accrued Liabilities Accrued liabilities at April 30, 2019 and 2018, respectively, consisted of the following (in thousands):
table: 2019 2018
table: Vacation and other compensation $1,659 $1,433
table: Incentive compensation 346 411
table: Payroll taxes 155 113
table: Deferred revenue - 68
table: Warranty reserve 529 520
table: Commissions 378 307
table: Other 504 564
table: $3,571 $3,416
question: Analyse this data from a financial earnings document. What is the difference in the total accrued liabilities between 2018 and 2019?