График частотности: упреждение

[{"date": "2015-08-30", "qty": 3}, {"date": "2015-12-03", "qty": 3}, {"date": "2015-12-04", "qty": 4}, {"date": "2015-12-05", "qty": 4}, {"date": "2015-12-06", "qty": 3}, {"date": "2016-02-01", "qty": 20}, {"date": "2017-04-29", "qty": 3}, {"date": "2017-06-10", "qty": 3}, {"date": "2017-06-11", "qty": 3}, {"date": "2017-06-26", "qty": 3}, {"date": "2017-07-21", "qty": 3}, {"date": "2017-10-09", "qty": 3}, {"date": "2017-11-14", "qty": 6}, {"date": "2017-12-03", "qty": 4}, {"date": "2017-12-24", "qty": 6}, {"date": "2018-02-21", "qty": 3}, {"date": "2018-03-02", "qty": 5}, {"date": "2018-06-03", "qty": 4}, {"date": "2018-06-28", "qty": 3}, {"date": "2018-07-16", "qty": 3}, {"date": "2018-07-18", "qty": 3}, {"date": "2018-07-23", "qty": 3}, {"date": "2019-03-09", "qty": 3}, {"date": "2019-03-30", "qty": 3}, {"date": "2019-04-04", "qty": 3}, {"date": "2019-06-21", "qty": 3}, {"date": "2019-08-26", "qty": 4}, {"date": "2020-02-16", "qty": 3}, {"date": "2020-06-16", "qty": 3}, {"date": "2020-12-07", "qty": 3}]