time |attendees|sales
-------------------------
 12:00 | 0  | 0
 12:15 | 0  | 0
 12:30 | 0  | 0
 12:45 | 0  | 0
 13:00 | 0  | 0
 13:15 | 0  | 0
 13:30 | 0  | 0
 13:45 | 0  | 0
 14:00 | 14 | 10
 14:15 | 30 | 250
 14:30 | 47 | 600
 14:45 | 59 | 900
 15:00 | 64 | 1100
 15:15 | 67 | 1300
 15:30 | 76 | 1400
 15:45 | 78 | 1420
 16:00 | 78 | 1500
 16:15 | 81 | 1600
 16:30 | 83 | 1650
 16:45 | 84 | 1700
 17:00 | 88 | 1780
 17:15 | 89 | 1800
 17:30 | 90 | 1850
 17:45 | 94 | 1900
 18:00 | 95 | 2000
 18:15 | 95 | 2005
 18:30 | 95 | 2080
 18:45 | 97 | 2100
 19:00 | 97 | 2120
 19:15 | 100| 2150
 19:30 | 100| 2180
 19:45 | 103| 2200
 20:00 | 103| 2250
 20:15 | 107| 2300
 20:30 | 109| 2350
 20:45 | 111| 2500
 21:00 | 111| 2600
 21:15 | 117| 2700
 21:30 | 119| 2800
 21:45 | 119| 2950
 22:00 | 120| 3000
 22:15 | 120| 3050
 22:30 | 150| 3050
 22:45 | 150| 3050
 23:00 | 180| 3050
 23:15 | 180| 3050
 23:30 | 180| 3050
 23:45 | 200| 3050
 00:00 | 200| 3050