Answer:
Market growth rate
Explanation:
The market growth rate refers to a rate in which the company is able to know how much it is growing it could be measured by comparing the prior years performance.
The BCG comprise of Boston consulting group that includes four things i.e. star, question mark, cash cow and dog in which the market growth rate is appears on the vertical axis, and in the horizontal axis, the relevant market share is displayed
Hence, the market growth rate is the answer