A minimum of organic views (not paid) is required to be considered for ranking. The ads are determined by an algorithm that takes into account paid and organic views, as well as audience engagement. A detailed description of the algorithm can be found on Thinkwithgoogle.com.
Top 5 video spots on youtube
1st Wella Professionals DE: Hairdressers Move
2. pepsimax: Drone Football | Pepsi Max | Genius. #LiveForNow
3. Hyundai Worldwide: Hyundai : A Message to Space
4th ZalandoTV: Switzerland (DE) // Tophshop@Zalando // #WhereverYouAre
5th Official Clash Of Clans: Clash of Clans: Ride of the Hog Riders (Official TV Commercial)