© Wine Market Council

Frequency of purchase by price point (weekly or monthly purchase by segment and price point)

And what are they drinking?

Want to identify a high-end wine drinker in the United States? Look for the guy drinking the bottle of assyrtiko.

While wines from most countries are purchased both by high-end and value-conscious Americans alike, Greek wines are the preserve of the first group – which is mysterious, because most Greek wines aren't that expensive.

"We talked to sommeliers and high-end buyers in New York and there's definitely something there," said John Gillespie, president of the Wine Market Council, during the release of its annual report last week.

"There's a large number of sommeliers and bloggers who are interested in wines from Greece. That's how these things happen. Now there's interest in indigenous varieties from Turkey. Any successful wine starts this way now: from the blogs and sommeliers."

The Wine Market Council studies U.S. wine consumers and has begun to focus on the differences between people who buy high-end wines – defined as wines on sale for more than $20 – and those who don't. Gillespie says $20 is the true demarcation line for high-end buyers, because "the same people who are buying wines over $20 are the people buying wines over $30, over $50, over $100."

Gillespie also sees them as a bellwether. "We know that the high-end wine buyers are much more sophisticated, and have tried and tasted many more wines than others," he said. "They are sort of in the middle between the level of sophistication of the trade and the level of sophistication of average consumers. But it is my feeling and observation that they are a great 'leading indicator' of where tastes and trends are going, so I personally think this is very good news for the people selling wines from Greece."

Only about 5 percent of the U.S. population ever buys wine over $20. In fact, the low number of everyday wine consumers is surprising given that this is the world's largest wine market. About 35 percent of American adults don't drink at all; another 21 percent drink beer or spirits, but not wine. Only 15 percent of the U.S. adult population drinks wine more than once a week.

The 30 percent of those who sometimes spend $20 for a bottle of wine will be of interest to the world's wine producers.

Here are a few facts about the 5 percent who drink wines over $20 and beyond:

They are equally likely to be male or female.

They are most happy with the quality of imported wine from France, Italy and New Zealand, and least happy with the quality of wine from South Africa.

However, they rate French wine lowest for "value" of any major wine-exporting country. Wine from Austria, Argentina and New Zealand is rated highest for value.

They are twice as likely as non-high-end buyers to purchase wines from France or Spain, and 60 percent more likely to buy wines from Italy.

They purchase domestic wine from Oregon, Washington and New York more often and believe that these wine-producing states provide as much value as any imported wine.

© Wine Market Council

Percentage of high-end vs. non-high-end buyers purchasing domestic wine from California and beyond in the past three months

As a group, they believe California wine is just behind French and Italian wine in quality – and above every other country – but not particularly close on value.

Opinions of California wine differ greatly on different sides of the Sierra Mountains. Californians are more likely than not to say California wine is of "excellent" quality, while Americans in other states are more likely to stop at "very good."

Wine reviews are still crucial: 70 percent of high-end buyers say reviews are very important for purchase decisions. The anti-critic movement has found greater sympathy from non-high-end buyers: only 19 percent of them say reviews are very important.

Fully 67 percent of high-frequency wine drinkers report drinking beer at least several times a week. Unsurprisingly, high-end buyers are more likely to drink craft beer.

High-end wine buyers are the main readers of wine information on the internet, with 56 percent reading wine blogs and 46 percent visiting Wine-Searcher. Only 11 percent of non-high-end buyers read wine blogs, and only 7 percent visit Wine-Searcher. (The other 93 percent don't know what they're missing.)

Related story:

Price Becoming "No. 1. Weapon" in U.S. Wine Market