19811221
       19811215      72.9
       19811221     100.0
       19811222      78.2
       19821201      75.7
       19851213      78.8
       19901203      82.2
       19901218      72.3
       19911223      81.4
       19911224      77.2
       19911226      82.9
       19931201      70.2
       19931205      81.5
       19931216      71.2
       19961205      71.2
       19961210      72.9
       19971223      81.5
       19971224      70.3
       19981209      70.1
       20001228      77.7
       20001230      70.1
       20011204      72.1
       20021202      75.4
       20021220      75.1
       20031212      70.8
       20031213      71.6
       20031216      83.8
       20031231      73.9
       20061221      78.5
       20071205      70.1
       20071229      72.2
       20071230      72.3
       20081210      88.4
       20091212      70.2