The IO500 benchmark has become the community standard for evaluating HPC storage system performance, yet the detailed data contained in its submission packages remains largely unexplored beyond aggregate leaderboard rankings. We present a statistical characterization of 61 IO500 submissions from four competition lists (ISC21 through SC22), examining score distributions, inter-phase correlations, and insights derived from detailed log files that accompany each submission. Our analysis reveals that IO500 scores span four orders of magnitude. Spearman correlation analysis shows strong within-domain clustering for both bandwidth (rs = 0.78 to 0.96) and metadata (rs = 0.89 to 0.98) phases, with the composite sub-scores exhibiting rs = 0.92 at per-node level (Pearson r = 0.53). Log-level analysis uncovers file-system-specific patterns in IOR close-time overhead, straggler behavior during the stonewall wear-down phase, and parallel-find load imbalance that are invisible in aggregate scores. These findings demonstrate that IO500 submission packages constitute a valuable research resource for understanding storage system behavior. The full submission dataset is publicly available at https://github.com/IO500/submission-data, and analysis scripts at https://gitlab-ce.gwdg.de/hpc-team/io500-analysis.