  We analyze a database comprising quarterly sales of 55624 pharmaceutical
products commercialized by 3939 pharmaceutical firms in the period 1992--2001.
We study the probability density function (PDF) of growth in firms and product
sales and find that the width of the PDF of growth decays with the sales as a
power law with exponent $\beta = 0.20 \pm 0.01$. We also find that the average
sales of products scales with the firm sales as a power law with exponent
$\alpha = 0.57 \pm 0.02$. And that the average number products of a firm scales
with the firm sales as a power law with exponent $\gamma = 0.42 \pm 0.02$. We
compare these findings with the predictions of models proposed till date on
growth of business firms.
