The two pie charts give information about how proportions of American expenditures have changed in 7 categories throughout 30 years (1966-1996).
At first glance, food and cars were the main expenses in 1966 and 1996, respectively. Both categories comprise the most significant changes over the period given. By contrast, computers and books were the least important expenses in the mid-60s and mid-90s, respectively.
On the one hand, a dramatic decrease of 30% can be seen on food expenditure reaching 14% in 1996. On the other hand, cars experienced a noticeably increase from almost a quarter of the pie chart (23%) to nearly a half of it (45%) within a time span of 30 years.
Regarding computers, there was a slight increase in its expenditure by up to 9% between 1966 and 1996. In terms of books, the figure fell mildly by 5% becoming the least important American expense in the mid-90s. Petrol, restaurants and furniture illustrate marginal differences from 1% by up to 7% during the period given.