Americans will pay more for their backyard barbecues this Fourth of July, according to the inaugural Rabobank BBQ Index. The index examines the composition of a 10-person barb­­ecue, showing an overall price increase from $51.90 in 2004 to a total of $66.82 in 2014.

Based on data from the Bureau of Labor Statistics, the Rabobank BBQ Index tracks the price of typical barbecue ingredients, from main dishes of...