To answer this, you need to know how many work days there are in one year. That depends on the company, its definition of a work week, and its number of allowable paid nonwork days (holidays, PTO, sick days, etc.). Employers and specific jobs can vary widely in this. One company could have 4-day work weeks, 10 paid holidays, and 21 days' PTO. Another could have 5-day work weeks, 8 paid holidays, and 15 days' PTO. Different answers, you see?
Then multiply by 9.