NEW YORK (AP) — Americans clicked away on their computers and smartphones for deals on Cyber Monday, which is expected to be the biggest online shopping day in history.

Shoppers are expected to spend $1.5 billion on Cyber Monday, up 20 percent from last year, according to research firm comScore. That would not only make it the biggest online shopping day of the year, but the biggest since comScore started tracking shoppers' online buying habits in 2001.

Online shopping was up 25.6 percent on Cyber Monday compared with the same time period a year ago, according to figures released Monday afternoon by IBM Benchmark, which tracks online sales. Sales from mobile devices, which include tablets, rose 10.9 percent. The group does not track dollar amount sales.