If you're in need of data relating to bee colony losses, the COLOSS association (Prevention of Bee Colony Loss) has the right tool for you. Through an interactive map, you are able to access information by country and year.
Gathering information from both public and voluntary sources, this map can help you review colony loss data trends since 2008. COLOSS established a network of surveys by country, covering a large portion of Europe, the United States, some North African countries and as well gathering information in the Middle East.
For more information, you may also check they've recently published BEEBOOK Volume III, including standard methods for Apis Mellifera research.