It doesn't.
Assuming you're referring to wind capacity additions, it most closely tracks the political winds in the U.S., in the form of the Production Tax Credit (PTC), a federal incentive program for construction of new wind capacity. The U.S. Department of Energy's Wind Vision report makes this relationship clear:

This chart ends at 2013 when the PTC was renewed for an additional two years. In 2015 it was renewed again for five years, but with a 20% per year phase-out. This means that the full impact of factors other than the PTC won't be visible until after 2020 (assuming the PTC won't be renewed again, which is likely as other factors will at that point be more important for driving new investment in wind).