Right on the CDC website.
In 1957, 115,000 died then when we had half the population.
https://www.cdc.gov/flu/pandemic-resources/1957-1958-pandemic.html
The estimated number of deaths was 1.1 million worldwide and 116,000 in the United States.
1957-1958 Pandemic (H2N2 virus) | Pandemic Influenza (Flu) | CDC
In February 1957, a new influenza A (H2N2) virus emerged in East Asia, triggering a pandemic (“Asian Flu”). This H2N2 virus was comprised of three different genes from an H2N2 virus that originated from an avian influenza A virus, including the H2 hemagglutinin and the N2 neuraminidase genes.
www.cdc.gov
Then in 1968. The estimated number of deaths was 1 million worldwide and about 100,000 in the United States. Most excess deaths were in people 65 years and older.
https://www.cdc.gov/flu/pandemic-resources/1968-pandemic.html
1968 Pandemic (H3N2 virus) | Pandemic Influenza (Flu) | CDC
The 1968 pandemic was caused by an influenza A (H3N2) virus comprised of two genes from an avian influenza A virus, including a new H3 hemagglutinin, but also contained the N2 neuraminidase from the 1957 H2N2 virus.
www.cdc.gov