Read the following texts and table with financial data from an S&P 500 earnings report carefully.Based on the question-answer history (if provided), answer the last question. The answer may require mathematical calculation based on the data provided.

Text: abiomed , inc . and subsidiaries notes to consolidated financial statements 2014 ( continued ) evidence of an arrangement exists , ( 2 ) delivery has occurred or services have been rendered , ( 3 ) the seller 2019s price to the buyer is fixed or determinable , and ( 4 ) collectibility is reasonably assured . further , sab 104 requires that both title and the risks and rewards of ownership be transferred to the buyer before revenue can be recognized . in addition to sab 104 , we follow the guidance of eitf 00-21 , revenue arrangements with multiple deliverables . we derive our revenues primarily from product sales , including maintenance service agreements . the great majority of our product revenues are derived from shipments of our ab5000 and bvs 5000 product lines to fulfill customer orders for a specified number of consoles and/or blood pumps for a specified price . we recognize revenues and record costs related to such sales upon product shipment . maintenance and service support contract revenues are recognized ratably over the term of the service contracts based upon the elapsed term of the service contract . government-sponsored research and development contracts and grants generally provide for payment on a cost-plus-fixed-fee basis . revenues from these contracts and grants are recognized as work is performed , provided the government has appropriated sufficient funds for the work . under contracts in which the company elects to spend significantly more on the development project during the term of the contract than the total contract amount , the company prospectively recognizes revenue on such contracts ratably over the term of the contract as it incurs related research and development costs , provided the government has appropriated sufficient funds for the work . ( d ) translation of foreign currencies all assets and liabilities of the company 2019s non-u.s . subsidiaries are translated at year-end exchange rates , and revenues and expenses are translated at average exchange rates for the year in accordance with sfas no . 52 , foreign currency translation . resulting translation adjustments are reflected in the accumulated other comprehensive loss component of shareholders 2019 equity . currency transaction gains and losses are included in the accompanying statement of income and are not material for the three years presented . ( e ) warranties the company routinely accrues for estimated future warranty costs on its product sales at the time of sale . our products are subject to rigorous regulation and quality standards . warranty costs are included in cost of product revenues within the consolidated statements of operations . the following table summarizes the activities in the warranty reserve for the two fiscal years ended march 31 , 2006 ( in thousands ) . <table class='wikitable'><tr><td>1</td><td>-</td><td>2005</td><td>2006</td></tr><tr><td>2</td><td>balance at the beginning of the year</td><td>$ 245</td><td>$ 231</td></tr><tr><td>3</td><td>accrual for warranties</td><td>198</td><td>193</td></tr><tr><td>4</td><td>warranty expense incurred for the year</td><td>-212 ( 212 )</td><td>-257 ( 257 )</td></tr><tr><td>5</td><td>balance at the end of the year</td><td>$ 231</td><td>$ 167</td></tr></table> .
Question: what was the balance of warranty reserves at the end of 2006?
Answer: 167.0
Question: what was the balance end the end of 2005?
Answer: 231.0
Question: what is the net difference?

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-64.0
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