Main: -Creates new file instance; -Applies a filter only for .csv format file; -Appends the path the the file name; -Creates ArrayList for years from 1900-2020; -Generates Reports through Hash;
Hash: -Hash map stores the frequency of the element; -Sort hash map by values; -Sort list by descending order; -Prints data; -Displays the occurrence of elements in the array list; -Prints data for the last 5 years and given year;