BTW, a typical incandescent bulb is 50 percent efficient.
No it isn't. High efficiency ones max out at 5.1%
Actually, a better way to measure the effectiveness of a light source is by it's luminous efficacy (values in the very link you provided). This gives a comparison of visible light that your eyes are sensitive to versus its consumption (lumens/watt). Eye sensitivity is relative to the black line, peaking at 555nm http://en.wikipedia.org/wiki/File:Luminosity.png
Even though a typical incandescent has 5.1% efficiency, it doesn't sound nearly as bad as it actually is because that's counting light emitted that you eye's aren't even sensitive to (mostly infrared and crap near the red, which you're really terrible at seeing). 
On a scale of 1-683 (the scale of efficacy), 16/683 yields 2.3%. Compare this to a sodium street lamp which has an luminous efficacy of around 25% by using that weird color you're very sensitive to.
For some interesting comparisons, http://en.wikipedia.org/wiki/Luminous_efficacy#Overall_luminous_efficacy
 Spectral Output of various sources, http://sam-steele.com/images/Spectral_Output.jpg