50% declining basis method over 31.5 years. 50% declining basis method over 39 years. k for follow up on 65 of 75. and deductions that reduce the depreciable basis include all of the following EXC etion 179 deduction ecial/bonus depreciation allowance. disabled access credit, enhanced oil recovery credit, and credit for employer-provided iness interest deduction. 50% declining basis method over 31.5 years. 50% declining basis method over 39 years. k for follow up on 65 of 75. and deductions that reduce the depreciable basis include all of the following EXC etion 179 deduction ecial/bonus depreciation allowance. disabled access credit, enhanced oil recovery credit, and credit for employer-provided iness interest deduction