The magic number is 100.
More is better if one is worried about preparation for the winter.
The number today: 94. At the link, scroll down to see the graph.
See "NG_Fill_Rate" at bottom of blog for past posts on this subject.
This link probably explains the most.
By the way, it's hard to see, but looking at the graph at the link to the EIA page (the first link above) the gap is widening from historical fill rate. At least that's what I see.
