Use the Report of vehicle work days
Click on the Vehicles icon in the main menu, and then on Report.
Click on the blue arrow beside the title and select Vehicles work days.
The list shows all your vehicles together with their work days for a specified year. Select the year to take into consideration from the arrows at the top of by writing it directly into the field.
On the right of each row, the total number of work days of that year are shown for a specific vehicle.
At the bottom of each row, you find that total number of work days for all of your vehicles for a certain month.
Finally, the number in the corner in the bottom right indicates the total work days of all your vehicle in the whole year selected.