human
management 2019s discussion and analysis net interest income 2013 versus 2012. net interest income on the consolidated statements of earnings was $3.39 billion for 2013, 13% (13%) lower than 2012. the decrease compared with 2012 was primarily due to lower average yields on financial instruments owned, at fair value, partially offset by lower interest expense on financial instruments sold, but not yet purchased, at fair value and collateralized financings. 2012 versus 2011. net interest income on the consolidated statements of earnings was $3.88 billion for 2012, 25% (25%) lower than 2011. the decrease compared with 2011 was primarily due to lower average yields on financial instruments owned, at fair value and collateralized agreements. see 201cstatistical disclosures 2014 distribution of assets, liabilities and shareholders 2019 equity 201d for further information about our sources of net interest income. operating expenses our operating expenses are primarily influenced by compensation, headcount and levels of business activity. compensation and benefits includes salaries, discretionary compensation, amortization of equity awards and other items such as benefits. discretionary compensation is significantly impacted by, among other factors, the level of net revenues, overall financial performance, prevailing labor markets, business mix, the structure of our share-based compensation programs and the external environment. the table below presents our operating expenses and total staff (which includes employees, consultants and temporary staff). .
|  | Year Ended December |
| <i>$ in millions</i> | 2013 | 2012 | 2011 |
| Compensation and benefits | $12,613 | $12,944 | $12,223 |
| Brokerage, clearing, exchange anddistribution fees | 2,341 | 2,208 | 2,463 |
| Market development | 541 | 509 | 640 |
| Communications and technology | 776 | 782 | 828 |
| Depreciation and amortization | 1,322 | 1,738 | 1,865 |
| Occupancy | 839 | 875 | 1,030 |
| Professional fees | 930 | 867 | 992 |
| Insurance reserves<sup>1</sup> | 176 | 598 | 529 |
| Other expenses | 2,931 | 2,435 | 2,072 |
| Total non-compensation expenses | 9,856 | 10,012 | 10,419 |
| Total operating expenses | $22,469 | $22,956 | $22,642 |
| Total staff at period-end | 32,900 | 32,400 | 33,300 |
1. related revenues are included in 201cmarket making 201d in the consolidated statements of earnings. goldman sachs 2013 annual report 45.
Please answer the following question with expressions if necessary.
and the percentage change?
assistant
subtract(32900, 32400), divide(#0, 32400)