Delivery issue to Outlook.com / Hotmail recipients; SNDS has no data for sending IPs

We are using AWS SES to send transactional emails to end users and have noticed that some emails are getting bounced.

During our investigation, we found that SNDS metrics can be used for proactive monitoring of Microsoft/Outlook email deliverability. However, these SNDS metrics are currently not visible in AWS CloudWatch for our SES dedicated IPs.

1. Could you please clarify the minimum email volume threshold required per IP per day for SNDS metrics to become available?
2. Also, do we need to maintain this threshold consistently on a daily basis for the SNDS metrics to continue appearing, or is it evaluated only when sufficient volume is observed for a specific reporting period?