What about these answers .....

• Very simply, I was paid by volume of production ... or on a commission basis.

• My objectives were very clear, and I often worked overtime to meet them.

• By ensuring that over 50 percent of the customer base remained loyal to the organisation.

• By generating a contribution that was five ties the size of my salary.

• I did my job with heart and I succeeded in .... (mention one or two achievements).

• I replaced two people for a period of two years in the largest department. 

• I decreased turnover by ... percent. 

• I took my responsibilities seriously to make sure nothing went wrong (for example, production never had to be stopped).