Final answer:
Over 20 percent of the world's countries have issued declarations of independence, marking their attempts to establish or maintain sovereignty.
Step-by-step explanation:
In today's world, a significant portion of countries have issued declarations of independence. Historically, these declarations have been part of the process for a region or nation to establish itself as a sovereign state.
Looking at the various secessionist movements and declarations over time, it is clear that more than 20 percent of countries have engaged in formal declarations of independence. This includes both successful and ongoing attempts to establish sovereignty.