Average Hours Worked from Home

A company conducted a survey about the number of hours employees worked from home over the past month. The results were as follows:

• 10 employees reported 0 hours
• 15 employees reported between 1 to 10 hours
• 20 employees reported between 11 to 20 hours
• 25 employees reported between 21 to 30 hours
• 5 employees reported more than 30 hours

Using this data, calculate the average number of hours worked from home by all employees who participated in the survey. Present your answer as a single number in the grid-in format.