FIGURE A.1 Numbers of purchases of cocaine base in four cities.

1996, there were more purchases in Washington, D.C., than in the other cities.¹ After 1996, there were more purchases in Boston than elsewhere. Throughout the period 1990–1998, there were more purchases in Washington, D.C., than in New York, although Washington, D.C., is a smaller city than New York. Boston is also smaller than New York, but in 1996– 1998 there were more purchases in Boston than in New York.

Figure A.2 shows year-to-year variations in the fraction of cocaine purchases of amounts of 5 gm or less in each of four cities. In New York, the fraction of such “small” purchases varies between 5 percent and 47 percent, depending on the year. The fraction of small purchases in Boston increased over the period 1990–1998, whereas there was no strong trend in the other cities. The fraction of small purchases tends to be lower in Detroit than in the other cities except in 1990–1991, when the fraction was lower in Boston.