The US Bureau of Labor Statistics releases reliable figures each year. For employers with consolidated PTO plans (vacation+sick leave+personal+family/medical), the average is 14 days after 1 year of employment. PTO is also typically accrued here. (You must earn PTO hours over the course of the year. Many employers allow hours to rollover to following years.)
For employers with separated plans, it’s 11 sick days and 11 vacation days per year after 1 year of employment.