График частотности: предложил

[{"date": "2010-12-16", "qty": 3}, {"date": "2010-12-17", "qty": 3}, {"date": "2010-12-20", "qty": 3}, {"date": "2010-12-22", "qty": 3}, {"date": "2010-12-27", "qty": 19}, {"date": "2010-12-28", "qty": 9}, {"date": "2010-12-31", "qty": 5}, {"date": "2011-01-06", "qty": 3}, {"date": "2011-01-11", "qty": 3}, {"date": "2011-01-12", "qty": 8}, {"date": "2011-01-13", "qty": 4}, {"date": "2011-01-14", "qty": 3}, {"date": "2011-01-15", "qty": 12}, {"date": "2011-01-16", "qty": 7}, {"date": "2011-01-19", "qty": 6}, {"date": "2011-01-20", "qty": 5}, {"date": "2011-01-21", "qty": 4}, {"date": "2011-01-22", "qty": 3}, {"date": "2011-01-25", "qty": 4}, {"date": "2011-01-26", "qty": 6}]