The property and casualty insurance industry is reeling from the largest year-over-year drop in net income in seven years, according to an analysis by Cambridge-based Highline Data, a division of Summit Business Media.

Net income was down 80.7 percent in the third quarter for the property and casualty industry compared with the same period in 2007 to $9.8 billion form $50.8 billion last year. Losses from Hurricanes Gustav, Hanna, and Ike were the main drivers of this decline. Additionally, the industry-wide loss ratio rose to 77.9 percent from 76 percent in the third quarter of 2007.

The last time the industry suffered a comparable decline was in 2001, which was driven by natural disasters and Sept. 11 losses.