TAIPEI, Jan. 8 (Xinhua) -- Taiwan's Consumer Price Index (CPI) recorded an annual average rise of 1.35 percent in 2018, the island's statistical agency said Tuesday. The CPI, a core measure of inflation, dipped 0.5 percent from the previous month in December, the first decline since November 2017, according to the agency. The agency mainly attributed the drop in December to price decreases for vegetables and fruit, communication equipment and electronic devices. However, higher prices for eggs, dairy products, cigarettes and medical expenses offset some of the decline. Chiu Chih-chang, chief economist of the Asia Pacific Region Development and Governance Society, said that overall CPI performance in 2018 was better than expected, noting that the devaluation of the new Taiwan dollar and price increases for international crude oil and raw materials led to rising import costs and higher commodity prices. Meanwhile, the Wholesale Price Index (WPI) was up 3.64 percent year-on-year in 2018. Chou Ji, an expert from the Chung-hua Institution for Economic Research, said that manufacturers on the island might reduce their production willingness as rising WPI would further raise import costs, adding that local authorities should improve the investment environment and eliminate administrative and legal obstacles holding back economic growth.