Table:
|  | Year Ended | Year Ended | Year Ended | % Variation | % Variation |
| --- | --- | --- | --- | --- | --- |
| 2019 vs 2018 2018 vs 2017 | 2019 | 2018 | 2017 | 2019 vs 2018 | 2018 vs 2017 |
|  | (In millions) | (In millions) | (In millions) |  |  |
| Automotive and Discrete Group (ADG) | $3,606 | $3,556 | $3,059 | 1.4% | 16.2% |
| Analog MEMS and Sensors Group (AMS) | 3,299 | 3,154 | 2,630 | 4.6 | 19.9 |
| Microcontrollers and Digital ICs Group (MDG) | 2,638 | 2,940 | 2,646 | (10.3) | 11.1 |
| Others | 13 | 14 | 12 | — | — |
| Total consolidated net revenues | $9,556 | $9,664 | $8,347 | (1.1)% | 15.8% |
Paragraphs:
For the full year 2019, our ADG revenues increased 1.4% compared to the previous period. The increase was primarily due to improved average selling prices of approximately 9%, which was entirely due to a better product mix, and partially offset by a decrease in volumes by approximately 8%.
AMS revenues grew 4.6%, mainly due to the double-digits growth in Imaging. The increase was due to higher average selling prices of approximately 12%, as a result of a better product mix, and was partially offset by lower volumes of approximately 7%.
MDG revenues were down by 10.3%, mainly due to Microcontrollers. The decrease was due to lower volumes of approximately 10% while average selling prices remained substantially flat.
In 2018, all product groups registered double-digit revenue increase. Our ADG revenues increased 16.2% for the full year 2018 compared to the full year 2017 on growth in both Power Discrete and Automotive. The increase was primarily due to improved average selling prices of approximately 21% and volumes decreased by approximately 5%. The increase in average selling prices was entirely due to improved product mix, while selling prices remained substantially flat.
AMS revenues grew 19.9%, mainly on the strong increase in Imaging. The increase was due to higher volumes of approximately 12% and higher average selling prices of approximately 8%, which was entirely due to improved product mix of approximately 13%, while selling prices decreased by approximately 5%.
MDG revenues were up by 11.1%, with Digital and Microcontrollers & Memories equally contributing. The increase was primarily due to higher average selling prices of approximately 11%, while volumes remained substantially flat. The increase in average selling prices was due to a better product mix of approximately 13%, while the selling prices effect was negative of approximately 2%.
Question:
In 2019, what was the reason for fall in MDG revenues?
Answer: MDG revenues were down by 10.3%, mainly due to Microcontrollers. The decrease was due to lower volumes of approximately 10% while average selling prices remained substantially flat.