attenuation "estimate" could have been affected by mash temps, grain crush and efficiency, ferm temps...lots of variables.
if its been steady for 2 weeks, you're probably ok. If concerned, you can try to raise the temp a few degree's, gently rouse up the fermentation chamber to see if you can get some yeast into suspension, and let it sit a couple days.
it would help to know grainbill, mash/ferm temps and yeast in use.