The Japanese chart assumes you are getting several times this from various--friendly! ;)--sources, but still it is the same order of magnitude.  

The German map is pretty well centered on one mS/yr.  

Since there is no safe level of radiation exposure (well, the universe just isn't a safe place, you know?--or rather, literally, radiation damage has no threshold.)  this is one end of your risk yardstick.  At the other end lies short exposures (within a few days) of 1000 mS (likely radiation sickness) or 6000 mS (LD50, even with medical treatment).  

In the middle:  At radiation levels below 10 mS/yr cancer rates tend to drop into the noise of cancers due to earth background, above that level they become statistically measurable.  

The Fates are kind.