The new retail e-commerce report, from eMarketer, states that US consumers have become so comfortable shopping online that they will increase their spending at online retail shops from $877 per consumer in 2005 to $1,512 per consumer by 2009 – an increase of more than 50%.

The report shows that, although the average annual growth rate of retail e-commerce sales will slow from the 26% seen between 2001 and 2005, it will remain robust at 18.6% from 2006 to 2009.

The retail sector of computer hardware and software is on the cusp of becoming the first category to derive a majority of its sales online, 54.5% by 2010, according to eMarketer calculations. But the categories of jewelry/luxury goods and health and beauty are making the deepest inroads into total sales, with online purchases expected to about double their percentage of total category sales by 2010.

Apparel, perhaps more than any other category, demonstrates the maturity of online sales and the comfort level of consumers. Apparel e-commerce as a percentage of total retail sales is expected to climb from 5.9% in 2005 to 11.4% by 2010, as specialized niche sites, high-end e-tailers and attention-grabbing technology converge to bring consumers online to buy clothes.

Online shoppers, who have faster online connections and more internet experience, are venturing beyond the safe purchase categories of books, videos and toys that marked the first e-commerce success stories, wrote eMarketer senior analyst Jeffrey Grau in the report.