According to the source (citation, Nr. 2017-0240-D) (PDF, machine translation):

For the period 2010 to 2016 the weighting of the SAKE data was revised. In our weighting procedure, we also take into account social insurance data for post-stratification. This allows for a higher statistical precision, in particular with regard to the labor market status (the unemployed / unemployed according to the ILO / non-employed persons). For some of the results, this revision generates a series break between 2009 and 2010. An adjustment of the time series for the period 1991-2009 was carried out for the ETS; Thus avoiding this series breakage, and a long time series can be maintained.

In response, we have archived the predecessors (prior methodology, as early as 1975Q1 to 2016Q4) by renaming with an "_16" specifier, by marking as "discontinued" and by segregating in the catalog. The one-for-one replacements (new methodology) start at 1991Q2. Figures are thousands of employees (Ths. #) not seasonally adjusted (NSA). Geo coverage is the nation and all seven NUTS 2 areas. Not all concept-geo pairs exist.

The series reside in the historical catalog (Switzerland » Labor and Wages » Employment Statistics (ES) » Employment » Quarterly by sex | Quarterly by sex and nationality) and include, for example:

• LWQEMTD_16UQ.ICHE  = [DISCONTINUED] Employment: All sectors - Swiss Nationals, (Ths.)
• LWQEMTDUQ.ICHE     = Employment - All activities - Swiss nationals, (Ths. #, NSA)
• LWQE2FUQ.ICHE_ZURC = Employment - Females, (Ths. #, NSA) - for NUTS 2 Zürich

Because catalog locations are subject to change, the upper-right search box on DataBuffet.com provides a "find in catalog" mode that accepts a mnemonic.

Please be aware that:

• In the replacement series, values are lower.
• The same methodological change impacted the "by industry" section of the dataset (see related article).
• Switzerland produces, and Data Buffet carries, several different employment datasets, including the SLFS, JOBSTAT and ES. In these mnemonics, "E2" is a fallback code when we have already used "EM".
• SAKE is the Schweizerische Arbeitskräfteerhebung (Swiss Labor Force Survey), a telephone survey conducted since 1991 by the BFS (Bundesamt für Statistik) (Federal Statistical Office).