〖例18-1〗我国1986－1992年彩色电视机销售数量资料如表18-1，试对该资料按年为周期进行定义日期。表18-1我国彩电销售量月度资料单位：万台1986198719881989199019911992149.848.939.250.162.580.678.5239.435.140.049.045.283.389.7325.825.930.937.543.948.349.8426.122.727.739.031.938.337.9522.621.629.830.432.630.934.5621.223.932.823.630.128.430.6721.725.337.717.829.728.932.2821.629.641.315.840.031.433.3931.829.338.318.153.939.340.11030.528.328.321.546.446.743.21129.026.927.520.345.748.642.91233.234.235.132.252.761.549.1数据文件：ctv.sav
