══════╤═════╤═════╤═════╤═════╤═════╤═════╤═════╤═════╤═════╤═════ │1903.│1904.│1905.│1906.│1907.│1908.│1909.│1910.│1911.│1912. ──────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼───── Jan. │ 170│ 179│ 198│ 195│ 180│ 239│ 166│ 119│ 115│ 187 Feb. │ 144│ 174│ 152│ 158│ 151│ 184│ 141│ 122│ 150│ 172 Mar. │ 112│ 126│ 143│ 135│ 132│ 153│ 152│ 86│ 168│ 143 Apr. │ 117│ 116│ 121│ 111│ 136│ 108│ 102│ 74│ 125│ 129 May │ 130│ 124│ 143│ 127│ 152│ 132│ 123│ 110│ 154│ 146 June │ 156│ 128│ 139│ 141│ 139│ 136│ 113│ 120│ 132│ 128 July │ 128│ 79│ 115│ 135│ 147│ 118│ 101│ 96│ 118│ 125 Aug. │ 133│ 120│ 115│ 138│ 128│ 105│ 92│ 112│ 116│ 103 Sep. │ 120│ 87│ 115│ 113│ 121│ 83│ 82│ 92│ 99│ 95 Oct. │ 109│ 110│ 135│ 121│ 104│ 131│ 91│ 107│ 124│ 118 Nov. │ 145│ 164│ 162│ 127│ 99│ 174│ 127│ 127│ 144│ 127 Dec. │ 194│ 184│ 178│ 148│ 172│ 184│ 138│ 136│ 145│ 147 ──────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼───── Totals│1,658│1,591│1,716│1,649│1,661│1,747│1,428│1,301│1,590│1,620 ──────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴───── ══════╤═════╤═════╤═════╤═════╤═════╤═════╤═════╤═════╤═════╤═════ │1913.│1914.│1915.│1916.│1917.│1918.│1919.│1920.│1921.│1922. ──────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼───── Jan. │ 182│ 157│ 200│ 239│ 224│ 157│ 256│ │ │ Feb. │ 149│ 145│ 166│ 193│ 162│ 212│ 212│ │ │ Mar. │ 141│ 127│ 149│ 157│ 131│ 232│ 155│ │ │ Apr. │ 129│ 103│ 109│ 119│ 116│ 190│ 147│ │ │ May │ 133│ 110│ 132│ 135│ 127│ 157│ 163│ │ │ June │ 149│ 139│ 130│ 128│ 114│ 121│ 182│ │ │ July │ 126│ 112│ 122│ 122│ 110│ 153│ 146│ │ │ Aug. │ 132│ 102│ 109│ 136│ 79│ 105│ 96│ │ │ Sep. │ 131│ 90│ 97│ 106│ 58│ 98│ 110│ │ │ Oct. │ 134│ 119│ 85│ 164│ 92│ 159│ 135│ │ │ Nov. │ 133│ 95│ 152│ 207│ 146│ 202│ 182│ │ │ Dec. │ 189│ 226│ 223│ 218│ 168│ 223│ 234│ │ │ ──────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼───── Totals│1,728│1,525│1,674│1,924│1,527│2,009│2,018│ │ │ ──────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴───── The next problem is to eliminate the normal seasonal variation. For example, hog prices have a normal tendency to go down in the fall of the year, whereas bank clearings have an equally normal tendency to go up. Obviously, seasonal trends must be eliminated if such series as hog prices and bank clearings are to be compared.