Cree PCT says 155 lm/W, 41.5lm, 2.67V for a XP-G3 R3 at the lowest measurement of 100mA. lm/W Efficiency seems to improve about 5% every time the current is halved, and lm/A 3%.
Extrapolating that I would guess about 33mA for 15lm, 10mA for 5lm, 2mA for 1lm. A bit more for the 219B because of higher CRI. At 1lm the driver could easily take more power than the LED.