Hi Christian,
The easiest way to access the most comprehensive historical price information available, would be through a bunkerworld.com premium subscription. You get access to prices from 1998 onwards, for over 220 ports and all major grades of fuels and distillates. To find out more, follow this link:
http://www.bunkerworld.com/store/tour#premium
Alternatively, if you require specific price data, say for a particular grade of fuel or a specific port, you could order price datasets. For such bespoke requirements, the best thing would be to contact the Bunkerworld office closest to you. Our contact details can be found on this page:
http://www.bunkerworld.com/contacts
I hope this answers your question.