The CPI(C) was formerly known as the Hang Seng CPI and was compiled by Hang Seng Bank. Starting from the reference month of July 1999, the data collection and compilation work of the index have been taken up by the Census and Statistics Department and the index has been renamed as CPI(C). Apart from being a standardization of titles, the renaming does not affect the compilation methodology nor the continuity of the index series. The 1989/90 based CPIs are based on the expendirure pattern of households which spent HK$17,500 to HK$37,499 a month in 1989/90. The average value for the period between October 1989 to September 1990 is taken to be the base index value of 100 for 1989/90 based CPI. The 1994/95 based CPIs are based on monthly spending between HK $30,000 to HK $59,999 in 1994/95.The base period for 1994/95 based CPI is between October 1994 to September 1995. The expenditure pattern are derived from the Household Expenditure Surveys.