 The senior population distribution is 3,675 people or 14.2% are 65–79 years old, 997 or 3.9% are 80–89 years old and 167 people or 0.6% of the population are 90+ years old.The population of Kriens has grown constantly since 1798.There were only three short periods of stagnation, the first from 1837–1850, the second 1910-1920 and the third 1970–1980.