NOTES TO THE CONSOLIDATED FINANCIAL  STATEMENTS  (RMB AND US$ AMOUNTS EXPRESSED IN THOUSANDS, EXCEPT PER SHARE DATA)  China Yuchai International Limited | Annual Report 2013 84 8.3  Research and development costs 8.4  Finance costs 8.5  Staff costs Yuchai and its subsidiaries have no obligation for the payment of pension benefits or any other post-retirement  benefits beyond the annual contributions described above. Note: Research and development costs recognized as an expense in the statement of profit or loss amounted to Rmb  468,612 (US$76,569) (2012: Rmb 373,732; 2011: Rmb 328,140). (i)  As stipulated by the regulations of the PRC, Yuchai and its subsidiaries participate in defined contribution  retirement plans organized by Guangxi Regional Government and Beijing City Government for its staff. All  staff are entitled to an annual pension equal to a fixed proportion of their final basic salary amount at their  retirement date. For the years ended December 31, 2013, 2012 and 2011, Yuchai and its subsidiaries were  required to make contributions to the retirement plan at a rate of 20.0% of the basic salary of their staff.  Expenses incurred in connection with the plan were Rmb 239,723 (US$39,170) (2012: Rmb 254,101; 2011: Rmb  239,253). 31.12.2011 31.12.2012 31.12.2013 31.12.2013 Rmb’000 Rmb’000 Rmb’000 US$’000 Wages and salaries 741,036 747,401 922,151 150,676 Contribution to defined contribution plans  (i) 240,590 254,101 243,614 39,806 Executive bonuses 67,347 43,773 56,501 9,232 Staff welfare 59,142 55,033 67,972 11,106 Others 1,888 5,094 2,336 382 1,110,003 1,105,402 1,292,574 211,202 31.12.2011 31.12.2012 31.12.2013 31.12.2013 Rmb’000 Rmb’000 Rmb’000 US$’000 Interest expense for: Bank term loans 33,693 70,557 65,458 10,695 Bills discounting 73,651 82,585 58,738 9,598 Corporate bonds 64,175 87,269 60,143 9,827 Bank charges 6,869 5,946 4,266 697 Less: Borrowing costs capitalized (Note 11) (22,214) (33,338) (27,394) (4,476) 156,174 213,019 161,211 26,341