CITIBANK LOWERS AUSTRALIAN PRIME RATE TO 16 PCT Citibank Ltd said it would lower its Australian prime rate to 16 pct from 16.5, effective tomorrow. The new rate, if unmatched by other banks, will be the lowest among Australian trading banks. Other primes range from 16.25 to 17.5 pct. Australian prime rates have now retreated from a recent peak of 19 pct in October in line with declining money market levels. Citibank said its reduction reflected the decline.