Here in CA there are many different rates, depending on classification.
Some workers comp rates I can remember are for operators, in general excavation, not trenching or other more hazardous things. If the pay is over $25 per hr, around 4%, if pay is under $25 per hr, it is around 8%. I guess they figure the higher paid worker is more experienced, and therefore less likely to be injured. Office and administrative is under 1%, while the highest classification I know of is roofers, at around 36%.
General liability is based on gross reciepts, and in 2000, it was running 0.7% on around 7 million in sales. It peaked in about 2006 or 2007 at around 3.5%, and that is with a far better than average record, not quite zero claims, but close. It has now dropped to around 2.5%