. . 10.2, ; 1981, 1968 .
. 10. 2. . : Booz, Allen and Hamilton (1982).
1 (36%) 5 (71%). : 50% 1968 . 70% 1981 . , , 1981 1968 .
, 1981 . : 21% 1 2 37% 3 10 28% 1968 . , 1981 . 25% 48% 1968 .
, . 1981 1968 . , 57 37%, 54%. . 10.3, , , .
1968 . 12 58 . 7. 3 , 2 - 1 , , . , , 58 .
1981 ., , 7 : 2% 1968 . 14%.
. 10.3. .
: Booz, Allen and Hamilton (1982).
, 1990 . PDMA (Page, 1993), : (9%).
100 , , 26, 6% ; 12, 4% 9, 4% (Page, 1993, . 284).
, , . .