The change rate is the maximum number of modifications (inserts,
deletes, and updates) made to the table per time period. Change
rate varies from table to table.
When planning capacity, always use a change rate greater than
the maximum change rate recorded for that table.
Note:
Figures for change rates are expressed as operations
per unit of time (for example, 5 updates per second).
Always use the same time period when calculating rates. If you measure
updates per second, then you must use seconds as the basis for all
other time period calculations.