the graph that you posted which cites Gallup data, does not appear to be consistent with what Gallup actually says: that gun ownership (as of 2011) is as high as it has been in roughly two decades. 47% of American adults have a gun in their home
Not surprisingly, the same survey concluded that women are buying firearms at higher rates and that Americans support gun rights more than they did 10 years ago.
Those results match my anecdotal experience. Gun stores, shooting ranges, gun shows, firearms competitions, and marksmanship clinics are constantly packed. People who own guns are buying more of them, but new owners are legion.