Well, to soothe Tim123's ruffled feathers, bench top dilute nitric acid that you might typically find in a chemistry lab like mine would commonly be 1M or 2M. But, as theprof says, there's no rule, and a lab using it a lot might well have a range of concentrations available, made up to suit their purposes. The most common grade of commercial concentrated nitric acid is around 68% (it's an azeotrope), which I think is around 15 M, but there are of course a number of grades available.