U.S. shoppers will spend $119.99 billion with online retailers during the upcoming holiday shopping season of Nov. 1 to Dec. 31, Internet Retailer estimates.

Online sales will increase 15.5 percent from the estimated $103.88 billion holiday shoppers spent online during the same period in 2017.

Total retail sales, excluding items not normally purchased online like fuel and automobiles, will jump 5.5 percent to $719.09 billion, up from $681.61 billion in November and December 2017, Internet Retailer projects.

That suggests e-commerce will represent 16.7 percent of all holiday retail spending, compared with 15.2 percent in 2017.

“The growth in U.S. e-commerce has been consistent since 2010, averaging 15 percent each year and showing no signs of slowing down. Add to that high consumer confidence, a healthy economy and strong 2018 online growth from retail giants like Amazon and Walmart, and we’re on track for a big holiday shopping season,” said Fareeha Ali, director of research strategy at Internet Retailer.

“Additionally, our research shows that more shoppers are turning to the web to purchase gifts during peak seasons. For instance, we estimate 24 percent of all Valentine’s Day purchases this year were online – far more than the overall 13 percent e-commerce penetration in 2017,” Ali said.

Several factors contribute to what Internet Retailer anticipates will be a record-high e-commerce holiday period.

For one, U.S. consumer confidence is at the highest level it has been in 18 years. The Conference Board’s Consumer Confidence Index, which is based on a survey that measures consumer sentiment on current economic conditions and prospects for the next six months, hit 133.4 in August.

This is the highest level since October 2000 and 11 percent higher than the August 2017 reading.

Further, more consumers are buying gifts online each year. Seventy six percent of U.S. shoppers said they purchased at least 25 percent of their gifts online during the 2017 holiday shopping season, according to a March 2018 Internet Retailer and Bizrate Insights survey, a 3-percentage point increase from shoppers who said the same after the 2016 holiday season.

For its holiday projections, Internet Retailer’s research team analyzed sales and growth in U.S. e-commerce and total retail over the last several years, identifying trends in consumer spending habits during peak shopping periods.

It also examined large online retailers’ growth patterns leading up to the holidays, historical e-commerce penetration of the overall retail industry and its trajectory, as well as economic indicators, such as U.S. consumer sentiment.

Internet Retailer Research provides data and information about e-commerce that helps retailers, investors and technology companies prosper. The team tracks hundreds of metrics on roughly 6,000 online retail companies around the world.