NEW YORK (AP) - More than half of Americans polled in a survey released on Thursday said they agreed with the statement "We are really in the era of Big Brother."

The survey from the University of Southern California was conducted last year, before recent revelations of large-scale, secret US government surveillance programs.

It found that some 35 per cent of respondents agreed that "There is no privacy, get over it."

A growing number of Internet users said they are concerned about the government checking on their online activities, according to the survey. But even more people were worried about businesses doing the same.

The USC Annenberg School's Centre for the Digital Future has polled more than 2,000 US households about their Internet and technology use each year, with the exception of 2011, since 1999.

Forty-three per cent of Internet users said they are concerned about the government checking what they do online, up from 38 per cent in 2010. But 57 per cent said they were worried about private companies doing the same thing - up from 48 per cent in the earlier study.

A 2012 survey by the Pew Research Centre found that almost three-quarters of Americans are concerned that businesses are collecting too much information about people like them, while 64 per cent had the same worry about the government.

The new report also found that 86 per cent of Americans are online, up from 82 per cent in 2010. That is the highest level in the study's history and further evidence of how central the Internet has become in American's lives, especially in the age of mobile devices.

"We find that people almost never lose their mobile phone," said Jeff Cole, author of the study and director of the centre.

"They can drop it in the gutter, have it stolen but leave it on the table at a restaurant - most of us don't even get through the front door before noticing it."

More than half of the Internet users surveyed said they go online using a mobile device, up from a third who said the same thing in 2010. As expected, texting is becoming increasingly important for people of all ages - 82 per cent of mobile phone users text, up from 62 per cent in 2010 and 31 per cent in 2007.

Among other key findings:

- Thirty per cent of parents said they do not monitor what their children do on social networking sites such as Facebook, while 70 per cent said that they do.

- Nearly half of parents, 46 per cent, said they have their kids' passwords so they can access their account.

- People spent more time online than in any previous year of the study. On average, they were online 20.4 hours per week, up from 18.3 hours in 2010 and about nine hours in 2000.

- One per cent of respondents said they visit websites with sexual content "several times a day," while 69 per cent said they never do.

The 2012 poll had a margin of error of plus or minus 2.7 percentage points.