Hi ,
https://documentation.meraki.com/MX/Monitoring_and_Reporting/Device_Utilization
MX device utilization can be retrieved using the API as well. The data reported to the dashboard and via the API are based on a load average taken every 60 seconds. The load value is returned in numeric value ranging from 1 through 100. A lower value indicates a lower load, where a higher value indicates a more intense workload. Currently, the load value is calculated based upon the CPU utilization of the MX and its traffic load.
The hyperlink "using the API" is no longer valid ( API v0 instead of v1 ). It should redirect to : https://developer.cisco.com/meraki/api-v1/get-device-appliance-performance/
Cheers ! 🙂