TOKYO, May 13 (Xinhua) -- The Japanese government's assessment of the economy released Monday marked the worst evaluation in more than six years as the nation grapples with slumping overseas demand and ballooning social welfare costs.

According to a preliminary report from the Cabinet Office, its coincident index of business conditions for March dropped 0.9 point from a month earlier to 99.6 against the 2015 base of 100, leading the office to lower its assessment of the key index as "worsening".

The Cabinet Office's expression of "worsening" is the lowest evaluation of the five terms it uses to assess its key index, and has not been used for the index since between October 2012 and January 2013.

The government's latest assessment comes on the heels of recent data showing that factory output here has slumped as demand from overseas has waned and could be a significant setback for the government of Prime Minister Shinzo Abe, who is seeking to raise Japan's consumption tax in October.