There is also an undertaking that any changes to the content of the letter, and any changes to the delegations, shall be made public. These commitments provide important safeguards of the independence of the HKMA in its day-to-day operations. I should add here that there has never in the past been any instance of the Financial Secretary's overriding or bypassing the Monetary Authority in the exercise of these delegated powers. So we would not expect to see disclosures of this kind very often. Nor would we expect to see frequent changes to the content of the letter or the form of the delegations, for an important part of operational independence is that it should be stable and predictable, and not something that is tinkered with at whim. The Exchange of Letters will, I believe, provide a clear basis for the HKMA to continue to carry out its work with a high level of autonomy in the years to come. Conclusion These will, naturally, be years of challenge for Hong Kong: there have been very few times in Hong Kong when this was not the case. The HKMA, as Hong Kong's central banking institution, has its part to play in helping Hong Kong meet the challenges. It also has its own special challenges. The main challenges in central banking are to maintain a monetary and banking environment that is optimal for stable and sustainable economic growth, and, particularly in the case of present-day Hong Kong, an environment that is conducive to resolving our current problems.
Mention should also be made of the reduction in spending on unemployment benefits, by 21.9% relative to the initial 2015 Budget. This is due to the fall in unemployment and in the coverage rate of the contributory benefit, which is partly offset by a shift in beneficiaries to non-contributory benefits, such as reinsertion scheme income and economic assistance under the activation programme for the unemployed. Finally, a further decline in the interest burden on government debt is foreseen as a result of the reduction in interest rates. On the revenue side, the main measures include the application of the second phase of the corporate income tax reform, and the impact over a full year of the related personal income tax reform. It is estimated the budgetary cost of these measures will be offset by the increase in revenue attributable to greater economic activity. Specifically, tax revenue before assignment to local and regional governments is expected to increase by 6.2% relative to the 2015 budget outturn projection, and Social Security contributions by 6.6% compared with the  4  BIS central bankers’ speeches  initial budget for 2015, which, given the macroeconomic forecast and the impact of the aforementioned tax reforms, would signify a greater response by revenue to the pattern of economic activity than that historically observed.