2. Generating an Accumulating Column within Groups The pg2.np_yearly Traffic table contains annual traffic counts at locations in national parks. Park names are grouped into park types. a. Open the p202p04.sas program in the practices folder. Complete the PROC SORT step to sort the pg2.np_yearlyTraffic table by ParkType and ParkName. b. Modify the DATA step as follows: c. Read the sorted table created in PROC SORT. d. Add a BY statement to group the data by Park Type. e. Create a column, TypeCount, that is the running total of Count within each value of ParkType. f. Format TypeCount so that values are displayed with commas. g. Keep only the ParkType and TypeCount columns. h. Run the program and confirm that TypeCount is reset at the beginning of each ParkType group. i. Modify the program to write only the last row for each ParkType to the output table