pre_text: Sales and Marketing Expense Sales and marketing expense increased by $18.1 million in 2019 compared to 2018. The increase was primarily due to a $15.5 million increase in employee-related costs, which includes stock-based compensation, associated with our increased headcount from 286 employees as of December 31, 2018 to 345 employees as of December 31, 2019. The remaining increase was principally the result of a $1.2 million increase in trade show and advertising costs and a $1.0 million increase attributed to office related expenses to support the sales team.
table: Year Ended December 31, Change
table: 2019 2018 $ %
table: (dollars in thousands)
table: Sales and marketing $ 87,731 $ 69,608 $ 18,123 26.0%
table: % of revenue 44% 47%
question: Analyse this data from a financial earnings document. What is the change in the % of revenue from 2018 to 2019?