Information on the importance of the dive to the overall visit was also included, and this was used to further scale the travel cost [20]. Diver income information was not collected directly, but respondents were asked to indicate if their income was higher or lower than their own national average income levels. A response of “much higher” was assumed to be 50% higher than their country's average, “higher” assumed to be 25% higher, “lower” assumed to be 25% lower and "much lower" assumed to be 50% lower than the national average of their home country.