oneThis plural form is used for numbers like: 1
In %1$d year
otherThis plural form is used for numbers like: everything else
In %1$d years
In %1$d year
In %1$d years
В %1$d год
В %1$d года
В %1$d лет
In %1$d year
In %1$d years
В %1$d год
В %1$d года
В %1$d лет
%1$d - number of years, %1$d may be skipped for singular if translation looks better.