According to a survey which Tokyo Metropolitan Government Bureau of Social Welfare and Public Health conducted in Tokyo during 2011-2012, 33% of dogs have their own dedicated toilets/potties, 65% of dogs excrete (poop) outdoors.
Figure 1: Where do dogs poop/pee? (number of sample = 298)
Generally it is recommended to pick up dog poops and not to leave them on the street.
91% of owners always clean up them.
Sometimes I actually see dog poops on the street. Some do not clean up.
Figure 2: Do you clean up poops after dogs excrete?
Source is Tokyo Metropolitan Government Bureau of Social Welfare and Public Health.