Benefit fraud cost taxpayers a record $22.6 million last year, and nine social welfare staff were sacked for ripping off the system.Figures released to the Herald under the Official Information Act show fraud detected by the Ministry of Social Development has tripled from $7.5 million five years ago.At that time, the ministry set up a fraud intelligence unit because of an international trend towards increasingly elaborate scams, including the use of stolen and faked identities,…