Yearly percentage change in California population and licensed chiropractors. The annual percentage of increase or decrease in California chiropractors from 1970 to 1998 was plotted with the solid line. The annual percentage growth in California residential population was plotted with the dashed line. The yearly percentage in licensed chiropractors exceeded the yearly percentage growth in population from 1977 until 1997. The disparity in growth rates reached its peak of 9% difference in 1985.