You probably never think about all the things going on inside of you. Don't you think it's about time you got to know yourself a little better? Here's your chance. This is all about you—by the numbers. Your Hair: - A healthy head of hair has anywhere from 80,000 to 150,000 hairs; brunettes tend to have 115,000 hairs, blondes have 140,000, and redheads have about 100,000. - Your hair grows at the rate of about a half inch every month. - You lose 50 to 150 strands of hair per day. - Half of us will be 50 percent gray by the time we reach the age of 50. - Your genes dete…