The researchers conducted a study following 1,315 subjects for 12 years.

One study that came close was conducted this year by Italian researchers.

Consider, for example, a study conducted by researchers in Finland.

In 2009 researchers conducted a survey of 2552 retired football players.

The researchers conducted a telephone survey of more than 1,100 patients, ages 14 to 17.

When the researchers conducted urine tests, the number rose to 65 percent.

The researchers conducted an examination of 831 homes in 75 locations around the country.

But studies conducted by other researchers have found rates as high as 43 percent.

The researchers conducted interviews with each of the family members and measured their stress levels throughout the day.

Those researchers conducted close to 500 telephone surveys and more than 400 personal interviews.