Only 4% of Americans have never made an online purchase. But that's not the important number.

Some 96% of Americans have made at least one online purchase in their lives and 80% in the last month alone, according to research from information and technology platform BigCommerce, Frost Investment Advisers said in a note on Tuesday, June 27.

Many of those sales likely went to e-commerce behemoth Amazon.com Inc. (AMZN) - Get Report

Stacy Mitchell, co-director of the Institute for Local Self-Reliance and co-author of "Amazon's Stranglehold," recently told TheStreet that one-fifth of the $3.6 trillion retail market in the U.S. is set to shift online, and Amazon is already on track to capture two-thirds of that share.

"Despite continuing improvement in retail sales, all channels are not benefiting," Tom Stringfellow, Frost president and chief investment officer, said in a statement regarding Amazon's expansion.

On Friday, June 16, Amazon announced its blockbuster $13.7 billion acquisition of organic grocer Whole Foods Market (WFM) , pushing it into yet another segment—grocery. Amazon already dominates tech and retail.

BigCommerce also found that 51% of all Americans prefer to shop online, while 67% of millennials and 56% of Generation Xers favor e-commerce shopping over in store. Some 41% of Baby Boomers and 28% of senior citizens make online purchases, according to Frost.

Amazon's shares fell 1.7% to $977.41 by Tuesday's close.

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