To calculate the average percentage of time spent on the phone per day, follow these steps:

1. Convert the average amount of time spent on the phone per day to a decimal. For example, if the average time spent on the phone per day is 2 hours and 23 minutes, convert it to 2.38 (
   Formula:

   2 + 23/60 

   ).
2. Divide the decimal value by 8 (total hours available in a day) and multiply by 100 to get the percentage. For example, if the decimal value is 2.38, divide it by 8 and multiply by 100 to get 29.75%.

So, the average percentage of time spent on the phone per day for the caller in this example is 29.75%.

To double-check your calculation, you can also calculate the total time spent on the phone as a percentage of the total time available in the month (assuming 20 working days in a month). If the total time spent on the phone is 100 hours in a month, the total time available is 160 hours (20 days x 8 hours per day). Dividing 100 by 160 and multiplying by 100 gives you 62.5%, which means the caller spent 62.5% of their time on the phone during the month. Dividing this by 20 (number of working days) gives you 3.125%, which is close to the 2.38/8 x 100 calculation we did earlier.