In a recent report on reinsurance Aon Benfield (here in PDF) includes the graph shown above which shows insured catastrophe losses worldwide as a proportion of GDP. Such a graph is not equivalent to a loss normalization of the sort that I often show. However, it does show that the re/insurance industries have managed (by design or by outcome) insured catastrophe losses such that there has not been a statistically significant trend in losses/GDP 1960 - 2011.
For those interested in weather-related losses (total, not just insured) at the global scale here is that data.