The average person blinks 15-20 times per minute, 1200 times per hour, and 28,800 times in a day.
The eye is protected by the eyelid. The eyelashes prevent dust and dirt from entering.
You blink to clean your eyes. Each eye is covered with a thin film of salty fluid, so every time you blink, the eyelid washes the eyeball and wipes away dust and germs. The water drains away through a narrow tube into the nose.
Also a new research indicates that the brain enters a momentary state of wakeful rest when we Blink, perhaps allowing us to focus better afterwards.