Chief executives of top US companies are slightly more upbeat about the nation\'s economic outlook but say political uncertainties are cramping growth, according to a survey released Tuesday. The Business Roundtable\'s second-quarter 2013 CEO Economic Outlook Survey showed the business leaders expect a minor improvement in economic output over the next six months, with modestly brighter expectations for sales and hiring offsetting a decline in capital investment. CEOs expected the economy to grow at a 2.2 percent pace, edging up from 2.1 percent seen in the first-quarter survey, said the pro-business lobby. \"Overall, CEOs see the US economy still on a slow road to recovery,\" said Jim McNerney, the head of aerospace giant Boeing. \"Relative to economic conditions, business performance remains strong, but the US government\'s unresolved long-term fiscal path and an uncertain political environment are key obstacles to more robust economic growth and hiring.\" The May 13-31 survey was based on responses by 141 CEOs. The survey\'s composite index for the next six months of sales, capital spending and employment jumped to 84.3 in the second quarter from 81.0 in the first quarter. Though it was the highest reading in a year, the number \"signals modest economic expansion,\" McNerney said in a conference call. He said he was \"hopeful\" that Congress, which has taken up immigration reform, would pass a balanced law that would help fill both higher-skill and lower-skill jobs that currently go begging. \"I see it in my world, in the science engineering and math capability that we need,\" he said of the lack of highly skilled job applicants. But McNerney was less optimistic about entitlement reform affecting the US social safety net for retirement and health care, crucial to long-term deficit reduction. \"There has been nothing substantive that\'s any closer to legislation than there was two months ago,\" he said. John Engler, the president of the Business Roundtable and a former Republican governor of Michigan, lamented the political uncertainty in Washington, with Congress deadlocked for months over passing the US budget for the fiscal year beginning October 1 and increasing the country\'s borrowing ceiling. \"Certainly the progress has been nonexistent, and in some ways is going in the opposite direction,\" he said in the conference call. \"The pressure points are building for the fall,\" he said. \"They\'re not going to deal with it until they\'re up against the wall with the deadline right in front of them.\"