The US debt interest-cost burden climbed to the highest since the 1990s in the financial year that’s just ended, escalating the risk that fiscal worries limit the policy options for the next administration in Washington.The Treasury spent $882 billion on net interest payments in the fiscal year through September — an average of roughly $2.4 billion a day, according to data the department released Friday. The cost was the equivalent of 3.06% as a share of gross domestic product, the highest ratio...