Who knew there were so many fascinating statistics and numbers behind this age-old art? Here are a few of our favorite factoids:

3400 B.C.

Era in which ancient Egyptians began using henna to camouflage their grays.

17: Age at which Marge Simpson went gray, according to her hubby Homer.

100 A. D.

Century in which Roman doctor Galen described a recipe for black dye. Scientists re-created the formula in 2006 and found it actually works.

11,000: Number of years ago scientists believe the genetic mutation for blond hair appeared.

60: Years since Wella invented Koleston Perfect professional color, used in Regis Salons.

1860

Approximate year hydrogen peroxide was first used as hair bleach, kicking off decades of broken strands and burned scalps.

92%: Women who have ever colored their hair, according to a Wella survey.

1907

Year the first synthetic hair dye was invented.

20: Number of minutes you must simmer crushed marigold flowers to make a rinse that adds reddish-gold highlights to hair, according to herbalists.

12: Number of hues of Regis clip-in extensions, including pink, purple, blue, red and green.

4,000: Number of people attending last year’s Roodharigendag (Redhead Day), an annual Dutch festival.

1953

Debut of Marilyn Monroe’s hit, Gentlemen Prefer Blondes. Its 1955 sequel, Gentlemen Marry Brunettes, was a bomb.

1931

Year “platinum blonde” was coined to describe Jean Harlow, star of the movie…wait for it…PLATINUM BLONDE.

1–2%: World population with naturally red hair.

1968

The last year Americans were asked to list hair color on their passports. (People were dyeing their hair so often, the information was worthless.)

# 1: Rank of black among most common hair colors.

9%: American women who are natural blondes.

# 1: Rank of blond among best-selling hair colors.

$51,000: Grant awarded to an Australian grad student to study whether or not blondes are actually dumb.

76%: U.S. women who think the first woman president will be a brunette, according to Allure magazine.

PHOTOS: WELLA; EVERETT COLLECTION