ABC Manufacturing Corporation is analyzing its sales data to identify long-term trends. The sales data over the last eight years is characterized by a consistent upward movement. The financial analyst determines that a linear trend model will best fit the data and expresses this model with the equation:
$$ S_t = eta_0 + eta_1 t + ext{error} $$
Where:
If the linear trend model indicates that $ eta_1 = 500 $, what does this information imply about the sales?