If Lavabit allowed large attachments, I'd say photos. 122KB is the average. The majority of emails were probably 1-2KB. Then newsletters, around 50KB. Lastly,

If Lavabit allowed large attachments, I'd say photos. 122KB is the average. The majority of emails were probably 1-2KB. Then newsletters, around 50KB. Lastly, emails with attached photos, ~5MB. Probably follows a simple Pareto distribution: 20% of emails comprised 80% of the total storage required.