pre_text: General and Administrative Expense General and administrative expense increased by $8.6 million in 2018 compared to 2017. The increase was primarily due to a $3.7 million increase in employee-related costs, which includes stock-based compensation, associated with our increased headcount from 79 employees as of December 31, 2017 to 89 employees as of December 31, 2018. There was an additional increase of $2.8 million in depreciation and amortization, an increase of $1.5 million to support compliance as a public company, an increase of $0.4 million in software subscription cost and a $0.2 million increase in office related expenses to support the administrative team.
table: Year Ended December 31, Change
table: 2018 2017 $ %
table: (dollars in thousands)
table: General and administrative $ 31,462 $ 22,895 $ 8,567 37.4%
table: % of revenue 21% 22%
question: Analyse this data from a financial earnings document. What is the average General and administrative expense for 2017 and 2018?