The firm, which has operations in Shropshire at Market Drayton, Minsterley and Telford, achieved a revenue of £1.9 billion for the year to December 31 2018, down from £2.1 billion the year before.
The German-owned company has also reported pre-tax losses of £100 million for the year compared with £134.1 million in the prior 12 months.
The results come after the firm created 65 new jobs earlier this year as part of a £50 million expansion at its Telford manufacturing facility.
Meanwhile, Müller Milk & Ingredients also confirmed plans in July to cut more than 200 permanent jobs and close its Foston Dairy site in Derbyshire.
The review was part of the company's Project Darwin, which was launched in February and is focused on cutting £100 million.
A statement signed off by the board said: "The Müller yogurt and dessert volume market share in chilled yogurts and potted desserts remained constant during 2018 and we continue to have leading brands in the yogurt branded market and a successful desserts partnership with Mondelez.
"Our value share declined slightly during the year due to fluctuation in promotional mix across our brands.
"The liquid milk market has changed significantly due to global market volatility, decline in consumption and changes in the retail environment, resulting in Müller Milk and Ingredients making losses during the reporting period.
"The partnership has invested significantly during the last year in increasing our yogurt production flexibility and capacity and is creating a class-leading liquid milk network with efficient dairies will fully recycled packaging capability."