staggering

The Art of ChoosingのAnd Then There Were Noneの章からの引用です。
There are now 4.5 million people living with Alzheimer's disease in the United States, and this number is expected to increase to a staggering 11 to 16 millon by 2050.
"stagger" に「よろめく」とか「ふらつく」の意味（あるいは名詞としても使われる）があるのは知っていますが、上の "stagger" は文脈からして「驚く程の」意味の様です。足がふらつく程驚いたと言うことでしょうか？ "stagger" を辞書で確かめます。
・Collins Dictionary: astounding or overwhelming; shocking ⇒ a staggering increase in demand
・Merriam-Webster's Online Dictionary: very large, shocking, or surprising: so great as to cause one to stagger: astonishing, overwhelming: a staggering feat: staggering medical bills
・Vocabulary.com: A staggering amount is an astonishing, astounding, stupefying amount. Anything staggering blows your mind.
If you know that stagger means to stumble around uncertainly, then you're close to the meaning of staggering: this is a word for things that are so hard to believe you might fall down when you hear them. If the President gets shot, that's staggering news. If there's a major earthquake, that's staggering. Alien life contacting the Earth would be extremely staggering. Anything that knocks your socks off or makes your mind reel is staggering.
確かに大地震が来たら足もふらついて驚きますね。慣用句の "knocks your socks off" に驚かすの意味があることは知っていましたが、こちらの表現の方がむしろ不自然ですね。
ところで最後に引用したVocabulary.comの説明に出てきた "reel" はやっと覚えることができました。（11/24/2009）