In conducting an extensive study on hand washing, researchers at Michigan State University uncovered some gross truths.

And the findings just might make you think twice about shaking someone's hand.

Turns out that after using the bathroom, 10 percent of people skipped washing their hands, 33 percent of people don't use soap, and worst of all, a whopping 95 percent of people don't wash their hands correctly.

You might be thinking to yourself right now: "That's not me. I am most definitely in the five percent that does it correctly." But are you?

The study found the average washing time for women is 7.07 seconds and for men it is 6.27 seconds. The Center for Disease Control and Prevention says people should wash their hands for 15 to 20 seconds, which would give them enough time to sing Happy Birthday twice.

The CDC say that the best way to prevent the spread of diseases is to wash your hands, so from now on you may want to think about warming up your vocal chords before you head over to the sink.

Here are the CDC's official tips for hand washing (apparently, almost everyone needs them):

• Get your hands wet by running them under any temperature water and lather on the soap.
• Start scrubbing your hands, ensuring that the soap is not only on your palm, but on the back part of your hand, in between fingers and under fingernails.
• After doing this for about 20 seconds rinse your hands.
• Using a clean towel or a drying machine, dry your hands.

Though most people don't wash their hands this thoroughly, hand washers are not entirely at fault for this lack of cleanliness.

The study found that the cleaner the sink, the longer the time somebody spent washing their hands. Also, only 64 percent of the public restrooms observed in the study had signs promoting hand washing.