how to calculate annual averages based on distinct combinations

So I have a table of 146510 rows. The schema and sample data are given below.      create table test2 ( year char(4) qtr char(2), area char(6), industry char(3), employment numeric(8,0) ); 2014,01,000019,722513,324 2014,02,000019,722513,330 2014,03,000019,722513,311 2014,04,000019,722513,347 2014,00,000019,722513,328 For every distinct combination of year, qtr, area, and industry, I need to produce a yearly average. The issue that I am running into is figuring out how to have it produce a 5th quarter. At the moment, there are 4 rows (due to having four quarters) per every combination of area and industry. I need to produce a fifth row that will have a q5 (or some value that represents average). First question is if there is a need to use the select distinct command? Second, do I use update to produce this fifth row?