Answer:
Rate of annual increase
Explanation:
Given that the expression
models the average annual per capita health care costs, in dollars, in the US as a function of the number of years t since 1970 .
1.076 in the expression
represents the rate of annual increase of the annual per capita health care costs (in dollars).
Take for example,
In Year 1, when t=1,

In Year 2, when t=2,

Once we know the annual per capita health care costs for the previous year, we simply multiply it by 1.076 or for any number of years, raise it to t years.