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 Soviet imperial frontier was imperative.[7] Between 1949 and 1961, over 2½ million East Germans fled to the West.[8] The numbers increased during the three years before the Berlin Wall was erected,[8] with 144,000 in 1959, 199,000 in 1960 and 207,000 in the first seven months of 1961 alone.[8][9] The East German economy suffered accordingly.[9]