46 million Americans lack health insurance: Survey

According to data from the study, the 2011 National Health Interview Survey, more than 21 percent of American adults do not have health insurance cover.

    "There has been a generally increasing trend in the percentage of adults aged 18-64 who lacked coverage at the time of interview," according to the study which was published on Tuesday.

The figures, however, show a small decline in the number of the youths who have no health insurance.

Many Americans also said they had trouble paying medical bills in the past year.

More than half of those with insurance said they had delayed in paying medical bills or skipped care in the past year due to out-of-pocket costs.

The survey comes as the US Supreme Court is set to rule on lawsuits challenging President Barack Obama's signature healthcare reforms. The ruling could halt key parts or the entire package.