How Many Recursive Calls Does a Recursive Function Make?

This paper looks at the number of function calls made to itself by a function calculating the Fibonacci numbers recursively. There is a linear relationship between the Fibonacci numbers and the number of recursive calls. The number of function calls for a number $n, G(n)$ is related to the Fibonacci number $F(n)$ by the relation $G(n)=2F(n)-1.$ This was achieved by adding a global counter to the recursive function and incrementing it each time the function is called.