According to a radio broadcast of the US National Oceanic and Atmospheric Administration (NOAA)'s NOAA Weather Radio KHB36 162.550 MHz (Manassas, Virginia) on May 24, 2022, a few minutes before 00:00 UTC,
Turn around, don't drown when encountering flooded roads. Most flood deaths occur in vehicles.
I have heard this statement read out on this station many times during times of heavy rain in the area.
I found a website at The Weather Channel which asserts in a pie graph that 64 percent of flood deaths (excluding Hurricane Katrina victims) from 1995 to 2010 occured "in vehicles", but the graph is not sourced.
A website of NOAA seems to provide access to flood statistics, but their page for 2020, the most recent year available, details that only 47.37% of flood deaths were vehicle or trailer-related. 47.37% is certainly high but doesn't really qualify as "most" since it does not represent a majority.
Do most flood deaths, at least in the USA, occur in vehicles? What evidence backs up this assertion?