The good old days. (Damian Dovarganes/AP Photo)

The self-proclaimed "King of Beers" is looking more like a pauper than a prince these days.

Budweiser sales have fallen each and every year for nearly a decade now, according to data from market research firm Euromonitor. The decline is such that Americans drink nearly 40 percent less of the famously mediocre mass brew than they did 10 years back. And it's even worse when considered on a per person basis: Americans, on average, now drink only 18 cans of Budweiser per year, more than 13 cans fewer than in 2004.

The fall from grace is so significant that The New York Post reports Budweiser is scrambling to re-brand itself in hopes that better marketing might help reverse the trend. It remains to be seen whether a fresh image can freshen up the beer's sales, but there's reason to believe its problems extend far beyond its ad campaigns.

What's going on? A few things, most likely.

Firstly, and probably most importantly, young people aren't drinking Budweiser. Even Budweiser admits that this is a major problem. And how could it not? Nearly half of young drinkers between the ages of 21 and 27 haven't even tried the beer, according to the company's own research.

Budweiser's tumble, meanwhile, coincides with a furious increase in craft beer, which stands for the very opposite of Budweiser—small batch (even if often unfairly). And that's likely of little coincidence. Big, non-craft beers have been suffering amid the rise of craft beer. Since 1998, non-craft brewers have lost more than 10 percent of the overall beer market, more than 5 percent of which has gone to craft brewers.

But Budweiser's troubles, however tied they might be to a country-wide shift from watery, mass-produced beers to less watery, less mass-produced beers, are also, and perhaps even largely, the result of a singular and growing distaste for Budweiser.

Similar, lower shelf beers, after all, haven't fared nearly as poorly. Bud Lite, Budweiser's waterier counterpart, and the most popular beer in America, has seen sales remain stagnant. So too have Miller and Natural. And a few brands, including Coors Light and Pabst Blue Ribbon, have even grown in popularity over the past decade—Coors Light by roughly 16 percent, and Pabst Blue Ribbon by nearly 130 percent, according to Euromonitor.