what is the variation of the additions during 2005 and 2006 , in thousands of dollars?
federal realty investment trust schedule iii summary of real estate and accumulated depreciation 2014continued three years ended december 31 , 2007 reconciliation of accumulated depreciation and amortization ( in thousands ) .

| Balance, December 31, 2004 | $595,338 |
| :--- | :--- |
| Additions during period—depreciation and amortization expense | 83,656 |
| Deductions during period—disposition and retirements of property | (15,244) |
| Balance, December 31, 2005 | $663,750 |
| Additions during period—depreciation and amortization expense | 89,564 |
| Deductions during period—disposition and retirements of property | (12,807) |
| Balance, December 31, 2006 | $740,507 |
| Additions during period—depreciation and amortization expense | 96,454 |
| Deductions during period—disposition and retirements of property | (80,258) |
| Balance, December 31, 2007 | $756,703 |

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additions_variation = 89564 - 83656
answer = additions_variation