"Service Credit" means: (a) 10% of the total invoice charges for the affected month if the Monthly Uptime Percentage for any calendar month is between 99.0% and 99.9%; or (b) 25% of the total invoice charges for the affected month if the Monthly Uptime Percentage for any calendar month is between 99.0% and 95.0 %; or (c) 50% of the total invoice charges for the affected month if the Monthly Uptime Percentage for any calendar month is less than 95.0%.
Source: https://gsuite.google.com/terms/partner_sla.html
Edit: It appears Microsoft/Office 365 offers the same SLA / 99.9%