According to the math in the previous response 390 ohms would be a 4.4% increase... 470/408 = 1.15 or a 15% decrease in current. It is my not so humble opinion that the 390 ohm resistor would be a better choice as it would increase the current by 1.1 mA, the 470 ohm resistor would decrease the current by 3.75 mA...
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