mW= 1/1000th of a watt.
mW=W = parts per 1000 efficiency.
480mW/W = 0.48W of light out for every watt of electricity in.
This is a deep blue LED.
It is very bad if you measure it in lumens per watt because the eye is quite insensitive to blue light.
Whatever the answer - 30%/44% (and you can't do it that way, you've got to integrate over the spectral response of the eye and see if you actually care about colour - green light at 600lm/W is not a functional white light) - is still vastly higher than 10%.
You cannot get the highest efficiency per watt LED bulbs, simply because they would require more LEDs than are absolutely required, and cost more, for no consumer visible benefit other than the watts.