The U.S. Treasury’s sale of $13 billion in 30-year bonds attracted higher-than-average demand as international investors sought higher returning securities with European sovereign-debt yields close to historic lows. The bid-to-cover ratio, which gauges demand by the amount bid with the amount offered, was 2.67, compared with an average 2.4 at the past 10 sales. The difference in 10-year yields vs.