The ones that know the lyrics and sing loudly: Pisces, Aquarius, Cancer
The ones that know the lyrics but don't sing: Virgo, Taurus, Capricorn
The ones that don't know the lyrics but sing anyway: Aries, Sagittarius, Leo
The ones that don't know the lyrics and don't sing: Gemini, Libra, Scorpio
I usually don't listen to the radio but somehow I know the lyrics xD