Japan’s inflation hit its fastest clip in 40 years in October, an outcome that puts the central bank in an even more awkward position as it tries to explain the need to stick with monetary stimulus to pursue stable price growth.

Consumer prices excluding fresh food climbed 3.6% in October from a year ago, with the acceleration driven by processed food and the fading impact of mobile phone fee cuts, the internal affairs ministry reported Friday.

The reading outpaced a 3.5% forecast by analysts and marks the fastest price growth since 1982. Core inflation has now exceeded the Bank of Japan’s 2% price target for seven straight months, with the yen’s historic fall amplifying the trend.