US opioid crisis: Falling number of overdoses give reason for hope / U.S. overdose deaths continue a rapid decline / U.S. overdose deaths are down, giving experts hope for an enduring decline / US overdose deaths are down, giving experts hope for an enduring decline / Is there finally hope in America's overdose crisis? / NPR Exclusive: U.S. overdose deaths plummet, saving thousands of lives / As losses mount in toxic opioid crisis, Ontario cities memorialize overdose victims / Opioid deaths in Ontario shelters more than tripled during pandemic, study finds