Table:
|  | Fiscal 2019 |  | Fiscal 2018 |  |
| --- | --- | --- | --- | --- |
|  | Amount | Percentage of total net sales | Amount | Percentage of total net sales |
| OEM Laser Sources (OLS) | $886,676 | 62.0% | $1,259,477 | 66.2% |
| Industrial Lasers & Systems (ILS) | 543,964 | 38.0% | 643,096 | 33.8% |
| Total | $1,430,640 | 100.0% | $1,902,573 | 100.0% |
Paragraphs:
Segments
We are organized into two reportable operating segments: OLS and ILS. While both segments deliver cost-effective, highly reliable photonics solutions, OLS is focused on high performance laser sources and complex optical sub-systems, typically used in microelectronics manufacturing, medical diagnostics and therapeutic applications, as well as in scientific research. ILS delivers high performance laser sources, sub-systems and tools primarily used for industrial laser materials processing, serving important end markets like automotive, machine tool, consumer goods and medical device manufacturing.
The following table sets forth, for the periods indicated, the amount of net sales and their relative percentages of total net sales by segment (dollars in thousands):
Net sales for fiscal 2019 decreased $471.9 million, or 25%, compared to fiscal 2018, with decreases of $372.8 million, or 30%, in our OLS segment and decreases of $99.1 million, or 15%, in our ILS segment. The fiscal 2019 decreases in both OLS and ILS segment sales included decreases due to the unfavorable impact of foreign exchange rates.
The decrease in our OLS segment sales in fiscal 2019 was primarily due to weaker demand resulting in lower shipments of ELA tools used in the flat panel display market and lower revenues from consumable service parts.
The decrease in our ILS segment sales from fiscal 2018 to fiscal 2019 was primarily due to lower sales for materials processing and microelectronics applications, partially offset by higher sales for medical and military applications within the OEM components and instrumentation market.
Question:
What led to the decrease in the OLS segment in 2019?
Answer: primarily due to weaker demand resulting in lower shipments of ELA tools used in the flat panel display market and lower revenues from consumable service parts.