http://www.dw.com/embed/640/av-18702933
By 1960, the combination of World War II and the massive emigration westward left East Germany with only 61% of its population of working age, compared to 70.5% before the war.[37] The loss was disproportionately heavy among professionals: engineers, technicians, physicians, teachers, lawyers and skilled workers.[37] The direct cost of manpower losses to East Germany (and corresponding gain to the West) has been estimated at $7 billion to $9 billion, with East German party leader Walter Ulbricht later claiming that West Germany owed him $17 billion in compensation, including reparations as well as manpower losses.[37] In addition, the drain of East Germany’s young population potentially cost it over 22.5 billion marks in lost educational investment.[40] The brain drain of professionals had become so damaging to the political credibility and economic viability of East Germany that the re-securing of the German communist frontier was imperative.[41]
The barrier was built slightly inside East Berlin or East German territory to ensure that it did not encroach on West Berlin at any point. Later, it was built up into the Wall proper, the first concrete elements and large blocks being put in place on 17 August. During the construction of the Wall, National People’s Army (NVA) and Combat Groups of the Working Class (KdA) soldiers stood in front of it with orders to shoot anyone who attempted to defect. Additionally, chain fences, walls, minefields and other obstacles were installed along the length of East Germany’s western border with West Germany proper. A huge no man’s land was cleared to provide a clear line of fire at fleeing refugees.[46]