Have your time in and out of your office logged, the time you spent every day at work automaticaly calculated, the averages of all arrival, departure times... in a google drive worksheet.
Try it. You won't be disappointed
Here is an example:
https://docs.google.com/spreadsheets/d/1tepTGjQQj_VbovZIqxhLc8Ua7CB2zvB6WC8rquSmjOk/edit?usp=sharing
Popular services on IFTTT