According to the U.S.Census Bureau’s figures, the state of Missouri has grown in population from 5,595,211 in 2000 to 5,988,927 in 2010. This represents a population growth of approximately 6.6% in this time frame. Please note, however, that there are two Episcopal dioceses in Missouri and that this one encompasses the eastern portion of the state and its see city is Saint Louis. According to the U.S.Census Bureau’s figures, Saint Louis as a city went from a population of 348,189 in 2000 to a population of 318,069 in 2010, a decline of about 9.5%.
According to Episcopal Church statistics, the Diocese of Missouri went from Average Sunday Attendance (or ASA) of 5185 in 2000 to 4128 in 2010. This represents a decline of 20.4% during this decade. Doing some historical digging, I noticed that the Average Sunday Attendance (or ASA) in 1994 for Missouri was 5644.
To see a pictorial representation of some of the statistics for the diocese of Missouri you may examine the graph here.