(YELLOWSTONE N.P.) — The number of visitors to Yellowstone National Park dropped slightly in July, compared to last year. Over 888,000 visited the park in July, 2.1 percent less than the 907,000 visitors in July 2011. Park officials remain optimistic, however. The number of overall visitors for the first seven months of 2012 was up by more than 100,000 compared to last year.