The polar bear is found in the Arctic Circle and some big land masses as far south as Newfoundland. While they are rare north of 88°, there is evidence ___61___ they range all the way across the Arctic, and as far south as James Bay in Canada. It is difficult to figure out a global population of polar bears as much of the range has been ___62___(poor) studied; however, biologists calculate that there are about 20,000-25,000 polar bears worldwide. Modern methods ___63___ tracking polar bear populations have been employed only since the mid-1980s, and are expensive ___64___(perform) consistently over a large area. In recent years some Inuit people in Nunavut ___65___(report) increases in bear sightings around human settlements, leading to a ___66___(believe) that populations are increasing. Scientists have responded by ___67___(note) that hungry bears may be congregating(聚集) around human settlements, leading to the illusion(错觉) that populations are ___68___(high) than they actually are. Of ___69___ nineteen recognized polar bear subpopulations, three are declining, six ____70____(be) stable, one is increasing, and nine lack enough data.