Field help (FASDEPRAT) 

Enter the depreciation annual rate to apply to the asset amount to value its depreciation expenses.
Based on the selected depreciation method, this field can be initialized according to the specified duration. Thus, in the case of a Non depreciated or depreciated asset based on the following methods: Ascending/Descending/Manual, you do not have to enter this field.
On the other hand, for theDeclining method, the suggested value can be modified, which is not the case when the Straight-line method has been chosen.
For the Straight-line depreciation, this rate is applied every year to the total amount, for the Declining depreciation, the rate is applied to the net value.