 The median age in Sarnia is 44 @.@ 5 which is older than the Canadian median of 40 @.@ 95 , indicative of Sarnia 's aging population . According to the 2011 Census , Sarnia is predominately Christian as 28 @.@ 46 % of the population were Catholic , 12 @.@ 4 % were members of the United Church of Canada , 7 @.@ 3 % were Anglican , and 20 @.@ 06 % were of other Christian faiths , Muslim , or Jewish ; 28 @.@ 38 % professed no religious preference or were <unk> . The median income counting all persons 15 years old or older in Sarnia in 2010 was $ 29 @,@ 196 , while median family income was $ 76 @,@ 523 , both of which were slightly lower than Ontario 's , at $ 30 @,@ 526 and $ 80 @,@ <unk> , respectively . The cost of living in Sarnia , however , is significantly lower than it is in Ontario as a whole . The median value of a dwelling , for instance , is $ 179 @,@ 266 , compared to the $ 300 @,@ <unk> of Ontario as a whole . 
