However, the May CPI rose 1.4 percent on-year, the office said.
Three of the 11 groups of goods and services used to calculate the CPI saw month-on-month price declines. The transport group saw the strongest fall of 2.29 percent, followed by food and catering services with 0.41 percent and housing, electricity, water, fuel and building materials with 0.97 percent.
The groups of garment-headgear-footwear and education saw no fluctuations during the period, while all other groups recorded price increases.
In the first five months of 2020, the municipal average CPI increased 3.76 percent annually.