The income shares of the richest 20 per cent of households increased from 50 per cent
of total household income in 1975/76 to 55 per cent in 1988/89, but declined to 43 in 1990/91,
while the share of the poorest 20 per cent declined from 8 per cent to 4.5 per cent during the
same period (Sussangkarn, 1992).