The aggregate costs indicated above demonstrate the
importance of transportation to logistics and, in turn, the
importance of logistics to the US business economy. The
former relationship was never more evident than during the
time frame from 1982 to 1987 when the total cost of logistics
as a percentage of the GNP declined by 22 per cent (from
14.7 per cent in 1981 to 10.8 per cent in 1987). Robert V.
Delaney states that, "Competitive, reliable transportation
enabled logisticians to manage their distribution systems with
less inventory, in fewer locations and with increased
confidence". Using inflation adjusted dollars, Delaney shows
a $200 billion decrease in inventory investment in 1989
compared to 1980. Transportation as a percentage of GNP
fell from 8.0 to 6.3 per cent during this time period[2].