I had the same problem only probably double cuz I use so much pressure all the time. So I bought an item called InvisiGRIP at JoAnn Fabrics. It is a clear film, like a saran wrap, only sturdier, that clings to the underside of the rulers and that seems to help a lot. You get enough to do several rulers.
Donna
Oh, and the new/sharp blade makes a really, really big difference.