Returns the number of trips grouped by vehicle.

This endpoint counts the number of trips performed by the trackers of a given company or group and returns the counts grouped by the vehicle.
The call must include either the company_oid or the group_oid as your identifier.
Optionally, the call can include the following parameters:

• start_date and end_date. These parameters limit the time period of interest, i.e. only trips that fall in between these dates will be counted.
  If the end_date is omitted, the list will include all the trips from the start_date until now.
  If both dates are omitted, the list will include the trips of the last seven days.
• next and previous. These parameters provide the pagination functionality for browsing the returned list.
  When calling this endpoint for the first time without specifying any parameters, it will return the first 10 elements of the list, ordered by date.
  If there are more than 10 elements, the returned file will include the parameter next and/or previous.
  By passing the next parameter into a second call of the same endpoint, the next 10 elements will be returned. The response will also include a new next parameter if there are remaining elements.
  In the same way, by passing the previous parameter, the previous 10 elements will be returned.