Seniors-the 19% of the U.S. population who are 65 years and older-have lagged in Internet use. But now they are surpassing all other age groups when it comes to growth in online use. 11.5 million seniors regularly go online, and this number is expected to nearly double to 20.1 million by 2010, according to Jupiter Research. What’s more, the percentage of the senior population going online will increase steadily, Jupiter says. In 2010, online seniors are expected to represent half of the overall senior population, compared with about one-third in 2005. Online seniors also have higher average household incomes than offline seniors ($60,300 versus $31,992), and higher average household assets ($385,714 versus $178,083), according to Forrester Research. Seniors spent an average $281 online over a three month period, Forrester said.