Sentence:  For 5-year-intervals (referred to in the following as “<WSD>quintades</WSD>” in analogy to decades) there is a marked drop of absolute and relative publications frequencies since the 1990s with a maximum of 4.2 % in the <WSD>quintade</WSD> 1985–1989 and the minimum of 1.6 % in 2010–2014 (see Fig. 1). 
Meaning of the word marked with <WSD> tags:  A period of 5 years.