comScore figures published by Internet Retailer show online retail sales shot up 45 percent for the week ending March 20, rising to $1.59 billion. 2005 has been a wild ride for e-commerce, with sales growth showing very high volatility. Figures released two weeks ago showed 34 percent growth. The week between that one and this one showed only 8 percent growth. This week's figures of 45 percent growth contrast to Shoppertrak figures showing general retail sales up only 4.9 percent over the same period. comScore reports that online travel spending rose 46 percent to $1.32 billion.