BERLIN, Aug 21 - Germany's economy shrank 0.1 percent in the second quarter of 2003 as a drop in exports offset higher public spending, the Federal Statistics Office said on Thursday. In a breakdown of data first released last week, the Statistics Office said stock building by companies also contributed positively to gross domestic product in the second quarter, but private consumption stagnated despite reports from highstreet retailers of a pick up in sales. The statistics office also confirmed German GDP shrank in the first quarter, putting Europe's largest economy firmly in recession.///