Last year just 53 percent of Germans in the west of the country, and only 36 percent of those in the former east worked under the Branchentarifvertrag agreements. These are conditions agreed between trade unions and employers which apply to an entire industry across the country.
In 1970 around 70 percent of workers in West Germany, and 56 percent of those in East Germany worked under such conditions, figures from the Institute for Employment Research show.
The decline is expected to continue, said Susanne Kohaut and Peter Ellguth from the institute, in a statement. "In the long term, this tendency is clear," they wrote.
Yet Germany's service sector union Verdi said it was growing this year, with a net increase of around 4,000 members during the first five months of the year, it said on Monday.
"We have never experienced such a development," said Verdi head Frank Bsirske. He said around 68,000 people had joined the union, but that around 64,000 had left.
He said the increase in members was at least in part due to the many conflicts over pay in such areas as the aviation industry and retail.
And on Monday Amazon several hundred staff in Germany walked off the job at Bad Hersfeld and Leipzig in the third strike within the past month. The workers are calling for work and wage conditions matching the national retail and mail order industry agreement. Amazon's managers are not offering more than the wages paid in the logistics industry.