As for the comments responding to my post, it's apparent to a chimp that the U.S. and China are quite intertwined economically, but that doesn't mean the political situation is anything as close. I wouldn't be surprised to see statistics pointing to good trade ties between the US and Germany right up to the onset of WWII.
I researched this once for a paper. Don't have the ranking though. If I remember right, Germany was in the top 5 during many of those years. Additionally, subsidiaries of US companies operated in Germany (under German management) after formal declaration of war in Dec, 1941.
Year/Exports to/Imports from
1934/$109 mi/$78 mil
1935/$ 92 mil/$69 mil
1936/$102 mil/$80 mil
1937/$126 mil/$92 mil
1938/$107 mil/$65 mil
1939/$46 mil/$52 mil
1940/$ 0*/$05 mil
1941/$ 0*/$03 mil
*Officially, exports were banned to Germany by order of President of the US. There is evidence of "unofficial" transactions through 3rd parties.
"Historical Statistics of the United States, Colonial Times to 1970", US Government Printing Office, 1975, pg 903-906
Sorry, but no links available for the Link Police today.