500 n 

 450 

 400 H 

 350 



-g 300 

 o 



5 250- 



a. 



J 200- 

 150- 

 100 

 50H 



SALES 

 PRICE 

 COST 



rnnrpn 



I A 



M 



'I " 'I" 'I "'I' 

 J J A S 



1967 



N 



D 



T 



T 



J F M A M J 



' I" M' "I " 'I' 

 J A S O 



N 



1968 



20 

 19 



hl8 

 17 

 16 



15 

 14 

 13 

 12 

 11 

 10 

 9 



-8 



-7 

 6 



-5 



-4 

 3 

 2 



(-1 



c 



3 



o 



a 



<u 



c 



(U 



E 



o 



CO 



Appendix Figure 1 1 . — Fresh and frozen salmon steaks — weekly retail prices, purchase costs, and sales volume from a Chicago food 



chain store with 20 branches, 1967 and 1968. 



32 



