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 ) .

2005
2006
balance at the beginning of the year
$ 245
$ 231
accrual for warranties
198
193
warranty expense incurred for the year
-212 ( 212 )
-257 ( 257 )
balance at the end of the year
$ 231
$ 167

.

Question: assuming a similar change in warranty expense as in 2006 , what would the 2007 expense provision ( 000 ) ?
Answer: 302

Question: what was the percentage change in warranty reserve from 2005 to 2006?
Answer: -28%

Question: what was the net change in warranty obligations from the end of 2004 to 2006?
Answer: 78000