The research was conducted by network management company Parallel in the three months to February 2002. It revealed that, on average, general retail companies' Web sites surveyed were not available to customers for a total of three days per year.
Boots, the high street health and beauty retail chain, achieved only 98.4% availability. Troubled food and fashion retailer Marks & Spencer fared worse still, with 98.2% availability of its pages.
The prize for the worst performing Web site went to the Shire Pharmaceutical Group, which was offline for 5.3% of the three-month period of the survey - equivalent to 20 days per year.
Web site availability was not the only problem suffered by the companies surveyed, according to Parallel. At 60Kbytes, the average home page size was twice the level recommended by industry experts. Boots was again a culprit, with the sixth largest Web page size, although media group EMI was way ahead of the rest with a massive 610Kbytes - more than 10 times larger than the average size.
Parallel said companies should focus on reducing Web site size because most customers do not have broadband connections and become frustrated waiting for pages to load.