My scan of the blockchain data for OP_RETURN outputs > 83bytes, prior to block 930600, when the default size setting was updated to 100000 bytes, is complete. I started at block 290,000, since thats about where the OP_RETURN field was introduced.

```

=========

RESULTS

=========

Scan range: blocks 290,000 to 930,599

Time elapsed: 27.56 hours

Average speed: 6.5 blocks/second

Blocks scanned: 640,600

Transactions scanned: 1,258,073,612

Transactions with OP_RETURN > 83 bytes: 577

Total OP_RETURN outputs > 83 bytes: 13,962

Size distribution by frequency (top 20):

142 bytes: 4,833 outputs

140 bytes: 2,931 outputs

138 bytes: 1,950 outputs

111 bytes: 420 outputs

137 bytes: 378 outputs

143 bytes: 247 outputs

122 bytes: 246 outputs

129 bytes: 237 outputs

139 bytes: 223 outputs

121 bytes: 198 outputs

118 bytes: 164 outputs

120 bytes: 140 outputs

131 bytes: 121 outputs

135 bytes: 76 outputs

141 bytes: 69 outputs

128 bytes: 65 outputs

132 bytes: 64 outputs

133 bytes: 62 outputs

153 bytes: 53 outputs

145 bytes: 46 outputs

... and 474 more distinct sizes

Size range: 84 - 984593 bytes

```

It is notable that the vast majority of outputs are using less than 150 bytes, so probably used by various scripts, rather than jpeg data.

This means that almost all of the spam is in non-prunable, permanent records, probably inscriptions.