The states hardest hit by the US housing bubble—Arizona, Nevada, Florida, and California—have registered the biggest rebound in small business marketing and sales activity since 2008, according to a recent analysis by CallFire.

The study used the purchase of local phone numbers by small businesses as a proxy for increases/decreases in economic activity since the collapse of Lehman Brothers.

CallFire examined local phone number purchase data in the continental United States from September 2008 through December 2012 to determine its state-by-state rankings.

Key findings of the analysis include the following:

• North Dakota, West Virginia, South Dakota, Iowa, and Mississippi were the states with the smallest increases in small business activity.
• North Dakota, which experienced huge economic growth during the time period examined, but was last. Why? Perhaps because much of the state's recent growth has been fueled by the shale oil and gas boom, which has benefited big firms but not necessarily small businesses.
• The same applies to the recent economic boom in West Virginia, which was driven by the mining industry.
• Washington State showed significant small business activity in the analysis, in large part because much of its recent growth has come from technology-focused companies that are more likely to purchase phone numbers.