of the euro area and in the rest of the world. within the euro area, the elimination of exchange rate risks and the lower transaction costs which followed, together with the far more transparent markets the euro brought with it, have created new opportunities for businesses and forced firms to attain higher levels of efficiency and competitiveness. a further success factor for the euro has been and still is its role as a catalyst in the process of financial integration, thereby enhancing the widening and deepening of the euro area financial markets. a large, liquid and integrated money market was rapidly created after 1 january 1999. this, in turn, triggered a significant growth of interest - bearing instruments denominated in euro. on the unsecured money market, the eonia ( euro overnight index average ) reference rate, an interbank overnight interest rate index compiled by the ecb, has established itself as one of the most important, perhaps even the most important, reference rate. the eonia swap market is now considered the largest overnight swap market in the world. in the bond market, too, the euro played a crucial role in fostering the deeper and more liquid euro area bond market that we see today. as early as in 1999, the total amount outstanding of euro - denominated debt securities made the euro bond market the second largest bond market in the world, and the international issuance of the euro - denominated bonds has even outpaced that of us dollar - denominated bonds for a few months at a time. at the international level, the euro has become the second most widely used currency as a result of the overall weight of the euro area economy in the world and the legacy of the national currencies which were replaced by the euro. looking at official international uses, the euro is second only to the us dollar among the world's official reserve currencies. the gap between the two currencies, however, is wide. according to the latest available data, the euro accounted for around 13 % of the world's official foreign currency holdings at the end of 1999, compared with a us dollar share of around 70 %. experience has shown, however, that there is a considerable time lag before the importance of a currency, as indicated by the economic weight of the country issuing that currency, is reflected in its use as an official reserve currency. as an anchor currency, the euro plays a role in the exchange rate regimes of more than 50 countries outside the euro area. the

the fact that inflation dynamics have been tepid indicates that historical averages may not be an appropriate benchmark for today ’ s policy stance and that corresponding benchmark levels must have fallen. policymakers need to be wary of these trends. they are probably rooted in receding growth rates in potential output and the legacy of financial factors that have emerged in the wake of the financial crisis ( like risk aversion and deleveraging pressures ). the degree of monetary policy accommodation, based on various real return measures, needs to be assessed relative to these benchmark trends in real yields. certainly, if these slow - moving trends in real yields are also taken into account, the current level of real interest rates provides an ample degree of policy accommodation. but interpreting their present levels against the background of their protracted downtrend and persistently subdued inflation underpins our stance that we have to be prudent, patient and persistent in calibrating our policy, as inflation will probably converge only gradually towards our objective. looking ahead, monetary policy will evolve in a data - dependent and time - consistent manner. once the governing council judges that the three criteria for sustained adjustment – convergence, confidence and resilience – have been met, net asset purchases will expire, in line with our guidance. from that point in time, inflation developments will remain conditional on reinvestments continuing for an extended period of time and on policy rates remaining at their 3 / 4 bis central bankers'speeches present levels well past the end of our net asset purchases. the stock of long - duration assets held in our portfolio will continue to put downward pressure on longer - term interest rates well beyond the end of our net purchases. policy rates remaining at their present levels well past the end of our net purchases will contribute to holding the short to intermediate portions of the yield curve in check for as long as necessary, thereby ensuring that financial conditions remain consistent with a sustained adjustment of inflation. see, for example, the european commission ’ s “ european economic forecast – autumn 2017 ”. potential growth was estimated at 1. 4 % for 2017 and 1. 5 % for 2018 and 2019. 2 for more details, see the box entitled “ the targeted longer - term refinancing operations : an overview of the take - up and their impact on bank intermediation ”, economic bulletin, issue 3, ecb, 2017. 3 see the ecb ’ s euro area bank lending survey, january 2018, and the ecb ’ s