Table:
Years Ended December 31,

Region	2017	2018	2019

%	%	%

Taiwan	32.8	36.4	36.4

Singapore	20.6	16.4	16.2

China (including Hong Kong)	12.7	12.2	12.9

Japan	3.2	3.9	6.6

USA	12.2	15.6	13.5

Europe	9.6	8.3	4.7

Others	8.9	7.2	9.7

Total	100.0	100.0	100.0

Answer the following question using the tabular data along with the context text, include the steps to get the answer if you wish, but end your response with {"answer": ["ANSWER"], "scale": "SCALE"} (scale blank when not needed).

Supporting text:
Customers and Markets
Our primary customers, in terms of our sales revenues, include premier integrated device manufacturers, such as Texas Instruments and Intel Mobile, plus leading fabless design companies, such as Broadcom, MediaTek, Realtek, Qualcomm and Novatek. Although we are not dependent on any single customer, a significant portion of our operating revenues has been generated from sales to a few customers. Our top ten customers accounted for approximately 51.3% of our operating revenues in 2019. Set forth below is a geographic breakdown of our operating revenues in 2017, 2018 and 2019 by the location of our customers.

Question: What is the increase / (decrease) in the customers from USA from 2018 to 2019?

(13.5% - 15.6% ) * 100, therefore {"answer": "-2.1", "scale": "percent"}