Americans will spend almost 50 percent more shopping online by 2016, a new report from Forrester Research suggests.

In 2011, Americans dropped $202 billion shopping online and this year, that number is projected to reach $226 billion. By 2016, online expenditures will grow 45 percent to $327 billion – a compound annual growth rate of approximately 10.1 percent over the five-year period. Eventually, online retail will account for 9 percent of total retail sales, a marked improvement over the 7 percent spent in 2012.

Forrester came to this conclusion by analyzing the monthly figures provided by the U.S. Census Department. Unlike the government organization, however, the researcher does not include sales of cars and trucks, gasoline, groceries and restaurant meals.

The big driver of sales won't be retail brands opening up new websites – many big retail merchants already have one – but the improvement of homepages and the services offered through them. A number of consumers have expressed dissatisfaction with the current online shopping experience and want more features from retailers, especially when it comes to high-end sellers.

"This is particularly true of categories such as apparel and jewelry, which have integrated rich selling tools such as zoom, color swatching and configurators, as well as office supply stores, which have broader payment options (e.g., small business purchase orders online) and subscription plans for their buyers," Forrester analyst Sucharita Mulpuru writes.

The number of shoppers is also growing steadily, thanks to improved accessibility from specific channels, such as smartphones and tablets. Nearly 200 million Americans will shop online in 2016, up 15 percent from the 167 million who do so today. Perhaps more importantly, though, is that the shoppers will spend considerably more online – the average ecommerce budget is slated to grow from the current $1,207 to $1,738 by 2016.

There is a perceived value to shopping on the web, which is another key driver of new sales. "Online shoppers believe that promotions available online are even better than what they could find elsewhere," the research added. This is why many Americans will prefer shopping online to brick-and-mortar retail stores.

Over the 2011 holiday shopping period, more than $50 billion was spent on ecommerce, according to separate data from comScore.