Amazon RDS - Cloudwatch shows 0.5 IOPS when not in use

Question

I recently set up an Amazon RDS instance for hosting a database. Even while I'm not using it, CloudWatch is showing a ReadIOPS of 0.2 - 0.3, and a WriteIOPS of 0.2-0.3. My service isn't live yet, so no one else could be using it.

Is this normal behavior? It's interfering with my ability to estimate how many I/O operations we're getting per user.