In the SLF homepage an interactive map with all deadly avalanche accidents over the last 20 years in the Swiss Alps can be found here.
Before you go on a ski tour it might be worth checking the map. There is, of course, no guarantee, of course, that if no deadly accidents were reported in the area you are planning to tour, it just might give you an indication how tricky the tour might be.
In early November 2016, the SLF has published a long term (80 years!!) statistical analysis of avalanche deaths in the Swiss Alps (see summary here). This new report (and its findings) has been also summarized in various Swiss newspapers. A link to the the complete study can be found here. Auch lesenswert ist der deutsche Artikel Entwicklung des Lawinenrisikos bei Aktivitäten im freien Gelände.
Generally speaking avalanche deaths (of off-piste and backcountry skiers) have been stable over recent years despite the strong increase of ski tourers and respective ski tours undertaken.