Thank you, Allen and good afternoon, everyone. I'll make a few comments about our operational performance and trends before turning things over to Janelle to present a summary of our financials.
I'll begin by discussing our top line.
As Allen noted, gross premiums written were up strongly in the first quarter by 19.0% year-over-year. This is the sixth straight quarter in which our top line has grown. Our first quarter increase in the top line was due to 2 factors: First, an 11.3% increase in premium on policies written during the quarter, what we refer to as deck sheet premium; and secondly, a strong year-over-year increase in payroll audits and related premium adjustments. Our debt sheet premium has now grown for 5 straight quarters and we have had 6 straight quarters of year-over-year increases in premium adjustments and very importantly, these increases have occurred while we have continued to increase our pricing.
We have also benefited from substantially higher average premium for both new and renewal business, as well as markedly higher renewal premium retention. Regarding our Renewal business, our first quarter premium retention was a very strong 97.2% versus 83.3% for the year ago quarter. This was due to increases in average per policy premium and we believe this provides more evidence of an overall firming of prices in our high hazard market segments. Our policy retention meanwhile, is 91.4% in the 2012 first quarter, lower than the 92.7% in the 2011 first quarter, but a strong figure nonetheless.
As mentioned above, our average premium for new and renewal business went up year-over-year in the first quarter from 30,800 per policy to 37,200 a 20.8% increase. This increase is due to a rise in both average payroll and to increased pricing for policies written during the quarter. Relative to pricing, our effective LCM for voluntary work comp in the first quarter was 1.59 or 159% of the approved loss cost of the states that use that mechanism for pricing. This compares to an ELCM of 1.45 in the first quarter of 2011 or a 9.7% increase. This compares to an increase of less than 1% year-over-year in Q1 '11.
We are encouraged by the fact that our business is growing even in the face of this significant increase in our pricing.
Relative to losses, our 2012 accident year has begun with both lower severity and lower premium based frequency than our 2011 accident year at 3 months or at the first quarter. As a result, we have made an initial estimate for 2012 that assumes a slightly lower net loss ratio, 76.5% than we estimated for the first quarter of accident year 2011. If we are correct, 2012 will become the fourth consecutive year in which Amerisafe has both the accident years loss ratios higher than 70%. We firmly believe that our results and the results of the industry as a whole have been significantly impacted by the cumulative effects of the efficient loss cost and increases in claims duration and that the impact of these factors won't really be known until the end of 2012 at the earliest. In the meantime, we are going to continue to push up pricing, tighten our underwriting and adjust claims as aggressively as we have in the past.
In terms of prior year losses, our first quarter financial results benefited from favorable overall development for accident years prior to 2012.
The loss ratio for our 2011 accident year, which is still green, remained at the 78.2% estimate we established in Q3 '11. Accident year 2010, the worst in our public history is still developing our case basis but at a much slowing rate. Case development for accident years 2009 and prior have been basically flat for the past 4 quarters.
We believe that our combination of prudent, both reserving and aggressive, claim management will serve us well as we work through our -- all of our open accident years but we faced very tough conditions in the claims world, characterized by high medical cost inflation, increased medical and pharmaceutical utilization and increased difficulty in returning injured claimants to work in times of high unemployment.
With that, I will turn to Janelle, to present details on our financials.