BERLIN, (Reuters) - Growth in Germany’s manufacturing sector slowed again in December as new orders fell at the fastest rate in four years, a survey showed on Wednesday.

Markit’s Purchasing Managers’ Index (PMI) for manufacturing, which accounts for about a fifth of the economy, fell to a 33-month low of 51.5 from 51.8 in November, edging closer to the 50.0 mark that separates growth from contraction.

It was the 11th time in 2018 that the manufacturing index fell, reflecting a sustained cooling of growth in Europe’s largest economy, which shrank in the third quarter partly on one-off effects such as fewer car registrations as makers adapt to new pollution standards.

Germany is also facing headwinds from trade frictions between the United States and China and weaker demand from the euro zone.

“With things having got a little too hot at the end of 2017 a correction was inevitable, but the extent of the slowdown has been somewhat a surprise,” said Phil Smith, principal economist at IHS Markit.

“The darkening global economic picture has had ramifications for Germany’s outwardly focused manufacturing sector over the course of 2018, while the sequence of headwinds in the car industry in the latter stages of the year has been a further restricting factor,” said Smith.

He added that manufacturers were able to sustain output growth thanks to back orders.