Per capita wine consumption

Active geocaches worldwide and US per capita wine consumption have grown together for eighteen years with a 0.97 correlation, implying that the global hidden-container hobby and American wine drinking are deeply intertwined activities. There are now over 3 million active geocaches hidden across the planet. Americans drink more wine per person than ever. The most plausible unified theory is that both activities involve wandering around and hoping to find something rewarding, and in this they are more alike than different.

Active geocaches worldwide grew from roughly 200,000 in 2005 to over 3 million by 2022 as smartphone GPS capabilities made the hobby accessible to mainstream participants without dedicated hardware. US per capita wine consumption grew steadily over the same period as millennial consumers aged into wine-drinking demographics, the domestic wine industry expanded, and broader beverage premiumization trends lifted wine at the expense of beer. Both are sustained growth curves across an eighteen-year window, correlating because they share a time axis rather than a cause.

Eighteen years of two things growing is an impressive-looking correlation and an unimpressive-looking explanation. Duration and direction are all that's required — the universe supplies the rest for free.