These may simply reflect a relatively unstable period of population adjustment.
During this unstable period, different types of mass media emerged.
Women helped sustain Paraguayan society during a very unstable period.
The late 1970s proved to be the start of a new and unstable period for international aviation.
"I am assigned to Earth during the late twentieth century, a very unstable period for them."
It lived unstable periods in the 1970s oscillating between the second and third group.
These defences were often reused during the unstable post-Roman period.
There was an unstable period due to mismanagement during the early years of the twentieth century, but sales revived in the 1930s.
The country went to an unstable period of economic decay and multiple short civil wars between states and parties.
Algeria is at the moment going through a very unstable period, facing all kinds of violence and showing little evidence of democracy.