Month   Year   Sold   Cord
   3    1980    141    6.4
   4    1980    166    6.1
   5    1980    161    5.7
   6    1980    170    6.9
   7    1980    148    7.0
   8    1980    136    7.2
   9    1980    169    6.6
  10    1980    109    5.7
  11    1980    117    5.7
  12    1980     87    5.3
   1    1981    105    4.9
   2    1981     73    5.4
   3    1981     82    4.5
   4    1981     75    6.0