1. Jack said "Backpacking amongst youth aged 6-17 decreased from 4.8% to 3.5%." That seems to be a drop of one-fourth and looks ominous. But the 4.8% is from 2006, before the survey changed methodology. If the range is instead from 2007 to the present, the change is 3.6% to 3.5%, which is statistically meaningless. . . .
2. As is much of the data, I'm afraid. When you have such tiny slices of the population, almost anything can throw off the numbers. Look at the youth participation since 2007: 3.6%, 4.2%, 3.7%, 4.4%, 3.5%. No rhyme or reason. Were the lower turnouts during years of poor weather? Did the lower-turnout years include better films that drew kids into theaters instead of outdoors? The higher percentages were in election years--did that influence the numbers? (Just joking.)
3. "Reaching out to minorities" isn't the most obvious way to increase the proportion of backpackers. If you want to sell an automobile magazine to new readers, market it to the demographic that already reads such magazines. You won't have as much luck trying to lure new readers from a demographic that tends not to read such magazines.
If, proportionately, whites go backpacking the most often and blacks the least often, your marketing effort will get better results by focusing on the former than the latter. (Assuming you had to choose one group over the other. Of course, everyone ought to be invited to participate.) If it were determined that lefthanded middle-aged women go backpacking disproportionately often, then market to other such women, if what you want is a raw increase in numbers.
Find out which subgroups backpack the most often, and reach out to those folks first. When that effort reaches a plateau, aim at the next-best group, and so on, working down the list. (This presumes the goal is increasing head count rather than trying to introduce backpacking to subgroups that rarely go backpacking now.)
4. One thing the report doesn't attempt to do is to correlate where people live with the frequency of their outdoor activities. Those who live in crowded metropolitan areas on the East and Midwest likely get outside less often than those who live in the Southwest and Mountain states, where activities may be just around the block. If you live in Detroit and want to go backpacking, the burden is greater than if you live instead in Reno. A good number of people in urban areas don't have cars because they use public transportation. Everyone in California has a car (or two). What trails can the city bus take you to, compared to what trails can your car take you to?