In addition to the luminous efficacy being from 10 to 186, the column next to it ( overall luminous efficiency ), should read 3% to 55%, not 1.5% to 22%. In fact, it looks like all the figures in that column are wrong. All they're doing apparently is dividing the lumens per watt by 683, which is the efficacy of monochromatic 555 nm green light. As all of the sources listed are not monochromatic green, doing this gives totally meaningless figures which have little to do with how much of the input power to the light source is actually emitted as light (which is what I assume the term "overall luminous efficiency" should refer to ). Or at least it does according to the definition given there:
"Artificial light sources are usually evaluated in terms luminous efficacy of a source, also sometimes called overall luminous efficacy. This is the ratio between the total luminous flux emitted by a device and the total amount of input power (electrical, etc.) it consumes. It is also sometimes referred to as the wall-plug luminous efficacy or simply wall-plug efficacy."
It should be obvious that in order to calculate the overall luminous efficacy you need to know something about the spectral distribution of the source, and DO NOT simply divide the luminous efficacy by 683.
