+-----------+--------+--------+
|   date    | data_a | data_b |
+-----------+--------+--------+
| 09-30-17  |    100 |    200 |
| 06-30-17  |     95 |    220 |
| 03-31-17  |     85 |    205 |
| 12-31-16  |     80 |    215 |
| 09-30-16  |     75 |    195 |
+-----------+--------+--------+