Hi Can someone tell me which is the dependent variable and independent variable in this question please?

Springfield, MA - Peter Pan Bus Lines (Travel and Tourism)

Springfield Massachusetts has long been known as a top vacation spot in the country, due largely to its beautiful weather, the Basketball Hall of Fame, and the home of Dr. Seuss.Peter Pan Bus Lines is a travel company specializing in providing public transportation to the region, and would like to make preparations for the upcoming year.Springfield city officials are expecting 17 million (17,000,000) tourists over the next year.As part of the planning process, Peter Pan has accumulated statistics for the past ten years pertaining to the total number of Springfield tourists, as well as the number of customers (i.e., ridership).The table for these results is included below:

Number of Tourists or Ridership?