2014 avg tariff chart at link. If we bump iours +5% we equal China...
http://www.indexmundi.com/facts/indicators/TM.TAX.MRCH.SM.AR.ZS/rankings
I would say start at 10% and see if it makes a dent in the trade deficit. Then increase it annually 2% until the deficit is close to balanced. We cannot afford to lose anymore industries to the 3rd world.
That chart is misleading because it is just tariffs.
VAT taxes that are charged on imports and credited to local manufacturers on their exports are much higher in countries that have them. China adds 17% VAT to American goods while it gives Chinese exporters a 17% credit. The EU countries do the same but with a 20% VAT.
Placing a 20% tariff on imports and using that revenue to issue 20% credits to our exporters would simply mirror what the EU and China do via their VAT and VAT-credit systems.