Analytics
Aggregate counts for a time range. Counts only, never rates.
Summarise sending
Totals for a time range. Counts only, never rates: the denominator for a rate depends on what you are measuring, so compute it yourself from these numbers.
Sending over time
Counts bucketed by hour or day, in UTC. Accepted, delivered and failed are bucketed by when the message was accepted. Opens, clicks and bounces are bucketed by when the event happened, so in a given bucket bounced can exceed failed.