767-200 is 17.9:1 (Boeing manual)
Was told by knowledgeable pilot that the 727 was 17:1.
Based on that I'd assume all modern airliners are very close to 18:1.
That would be at optimum L/D speed, which would be about clean min. manuever speed.
L/D ratio would decrease as flaps are extended. As BA 038 showed, based on the data given by the AAIB(108 KIAS, 1800 FPM sink), the fully configured glide ratio, right above stall, is about 6-7:1.