By the late 1990s, the popularity of this genre had started to decline slowly.

After the 1950s, the city's population began to decline slowly, as families tended to be replaced by single people and young couples.

The species was probably declining slowly since the mid-19th century.

This amount declines slowly as the americium decays into neptunium-237, a different transuranic element with a much longer half-life (about 2.14 million years).

However, the practice of catacomb burial declined slowly, and the dead were increasingly buried in church cemeteries.