In the UK they have 4 albums in the top 100;
Buckingham McVie #5
FM Greatest Hits #36
Very Best of FM #94
A (very quick) scan of the charts tells me they are the only artists with 4 albums in the top 100.
FM have consistently had 2 or 3 albums in the top 100 for several months. A lot of it is down to the Rumours anniversary. However, I think quite a lot is also a bounce coming from Buckingham McVie.