Reba McEntire was voted the greatest woman in country music over the last 20 years in a poll by CMT. No doubt Reba is one of the few artists to have a career last that long, man or woman.  But many other female singers chose to focus on family rather than career (Faith Hill), got tired of the limelight (Shania Twain) or shot themselves in the foot (Dixie Chicks.)  Check out the complete list and tell us your favorite female country singer.Reba has a career that spans more than 30 years.  Her first album was released in 1977 and she had her first top 20 hit in 1979.  Second place went to Carrie Underwood who wasn't even born until 1983.  Shania Twain, Taylor Swift and Martina McBride round out the top 5.  Get CMT's complete list of the