BOSTON ( TheStreet) -- By now we've all heard that the government shutdown has led to the closing of national parks and monuments across the country. What's the financial impact? According to data compiled by the National Parks Conservation Association, visitors spend more than $35 million each day in areas around the country's 401 national parks during the month of October -- that is, when they are open. Some local economies rely on national parks more than others. For instance, of that $35 million, nearly $4 million is spent by visitors to California's many national parks. But it is Washington, D.C.'s national park and monument areas that visitors spend more on than in any other state: about $4.5 million on a typical October day. Arizona also gets a large share of money, approximately $2.5 million daily, nearly half of which is spent in the Grand Canyon region. Of the 800,000 "non-essential" federal employees who have been furloughed, 21,000 are National Park Service workers. "The government shutdown makes a bad situation even worse for our national parks. Last year was the third straight year of budget cuts for the National Park Service," wrote Emily Douce, the NPCA's budget and appropriations specialist, on the official NPCA blog, ParkAdvocate.org. "Before the shutdown, the parks were already operating 13% below 2010 levels in today's dollars. If Congress passes a short-term budget deal, it will continue sequester levels, and parks will continue to be affected, including the staff." A bill introduced that would offer furloughed government employees back pay for the time they were forced to take off work made its way to an Oct. 5 vote in the House of Representatives.