The nation's key money supply gauge grew an average of 4 percent in 1998, up 0.9 percentage point from its 3.1 percent growth pace logged in 1997, the Bank of Japan said Tuesday.

The 4 percent rise, which is preliminary, is the highest since 1990, when the key money supply gauge — M2 cash in circulation and demand and time deposits plus certificates of deposits — grew 11.7 percent, the central bank said.

In December, the daily average of M2 plus CDs grew a preliminary 3.9 percent from a year earlier to 608.9 trillion yen, the BOJ said. The pace of growth in December is slower than in November, when M2 plus CDs expanded an average of 4.3 percent, according to the bank.

If M2 plus CDs at Japanese branches of foreign banks and those at Zenshinren Bank, an umbrella body of "shinkin" (credit) banks nationwide, are included, the amount came to 611.7 trillion yen, the BOJ said.

The broad measure of liquidity, which includes postal savings, deposits at farm and fisheries cooperatives, loan trusts and money trusts, bank debentures and government and foreign bonds, rose 3.1 percent for 1998, slower than a 3.5 percent rise in 1997.