Growth in U.S. online retail sales will slow over the next five years to an average of 11 percent, but offline sales will continue to benefit greatly from online research, according to a Jupiter Research study.

This year, U.S. online retail sales will grow 16 percent to US$116 billion, but the compound growth average will drop to 11 percent between 2007 and 2011, when sales will hit US$171 billion.

Although online sales growth will be in the single digits by 2010, offline retail sales influenced by online research will reach US$1 trillion by 2011, a compound growth average of 12 percent, according to the study "U.S. Online Retail Forecast, 2006 - 2011."

By 2011, 40 percent of all U.S. retail sales will be influenced by online research, Jupiter said Tuesday.

Over the coming decades, online retail sales will settle at 10 percent to 15 percent of total U.S. retail sales, Jupiter forecasts.