Table:
|  | 2019 | As a % of Revenue (1) | 2018 | As a % of Revenue (1) |
| --- | --- | --- | --- | --- |
| PSG | $ 2,788.3 | 50.5 % | $ 3,038.2 | 51.7 % |
| ASG | 1,972.3 | 35.7 % | 2,071.2 | 35.2 % |
| ISG | 757.3 | 13.7 % | 768.9 | 13.1 % |
| Total revenue | $ 5,517.9 |  | $ 5,878.3 |  |
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Revenue
Revenue was $5,517.9 million and $5,878.3 million for 2019 and 2018, respectively. The decrease of $360.4 million, or 6.1% was primarily attributable to an 8.2%, 4.8% and 1.5% decrease in revenue in PSG, ASG and ISG, respectively, which is further explained below. Revenue by reportable segment for each were as follows (dollars in millions):
(1) Certain of the amounts may not total due to rounding of individual amounts.
Revenue from PSG
Revenue from PSG decreased by $249.9 million, or approximately 8%, which was due to a combination of a decrease in volume of products sold and a competitive pricing environment. The revenue in our Protection and Signal Division, Integrated Circuits Division, and High Power Division, decreased by $106.5 million, $96.6 million and $91.5 million, respectively. This was partially offset by an increase in revenue of $30.1 million and $15.0 million from our Foundry Services and Power Mosfet Division, respectively.
Revenue from ASG
Revenue from ASG decreased by $98.9 million, or approximately 5%, which was also due to a combination of a decrease in volume of products sold and a competitive pricing environment. The revenue in our Industrial and Offline Power Division and our Signal Processing, Wireless and Medical Division, decreased by $100.5 million and $56.4 million, respectively. This was partially offset by $84.8 million of revenue from Quantenna, which was acquired during 2019.
Revenue from ISG
Revenue from ISG decreased by $11.6 million, or 1.5%, which was due to a decrease in our Industrial Sensing Division revenue of $20.8 million, primarily due to decreased demand, which was partially offset by an increase in revenue in other divisions.
Question:
What led to the decrease in overall Revenue between 2018 and 2019?
Answer: primarily attributable to an 8.2%, 4.8% and 1.5% decrease in revenue in PSG, ASG and ISG, respectively