the growth of industrial sectors theoretical insights and empirical evidence from us manufacturing sandro sapio grid thoma lem sant anna school advanced studies pisa italy 2006 09 march laboratory economics management piazza martiri della libertà 33 56127 tel 39 050 883 343 fax 344 email sssup it web page http www working paper series sapioy thomay y 6 abstract in this we study rates 4 digit manu facturing twomeasuresofsize valueofshipments valueadded areconsid ered for each 38 years 1959 1996 a sample 458 drawn nber productivity database whole sam ple results are partly line with flrm facts i sectoral distributed according to heavy tailed subbotin distributions shape coe cient between 1 0 laplace 5 ii volatility is decreasing respect size scaling exponent varying over