Lott also presents an analysis (page 114) based on two surveys of gun ownership (conducted in 1988 and 1996) that purports to show that a 1% increase in a state's gun ownership causes a 4.1% decrease in the violent crime rate and a 3.2% decrease in auto theft.
Lott's two polls indicate that gun ownership increased by 50% in just eight years, from 26% to 39%. This is contradicted by everything else we know about gun ownership:
Since 1959, there have been at least 86 different surveys on gun ownership . There doesn't seem to have been in any increase over that period, let alone over 1988-1996. The percentage of the population that declared they were gun owners varied between 25% and 35%, but there was no clear trend. It seems that the changes in the numbers are caused by sampling error, differently worded questions, and changes in the willingness of people to admit to gun ownership. Lott's apparent increase is an artifact of his having looked at just two polls instead of many.
Data on gun sales in the period 1988-1996 shows that the number of guns per person increased by just 10% [21,18]. Any increase in ownership rates is going to be less than 10% since the majority of gun purchases are by people who already own guns. Furthermore, gun sales per capita in the period 1988-1996 were only 5% more than in the previous eight year period. This does not seem consistent with the dramatic increase in gun ownership suggested by Lott.
Lott argues (page 36) that a doubling of spending on private security from 1980 to 1996 suggests that more people have been obtaining guns. However, despite an increase in population, gun sales in 1996 (4.8 million) were less than in 1980 (5.8 million).