In another sign that Europe’s economy is turning the corner, a leading ratings agency found Tuesday that the value of new stock market listings in 2013 recovered to match the 10-year average. Standard & Poor’s said 13 billion euros worth of new equity was floated last year and that the revival is set to continue this year, barring any economic or market shocks. The agency credited the advance on buoyant equity markets, pent-up demand from private equity owners and optimism over the European economy’s prospects. A risk-averse approach dominated sentiment across corporate boardrooms.