… is in commemoration of the 20th anniversary, which is today, of Hayek’s death. The quotation is from page 133 of Hayek’s last book, his 1988 The Fatal Conceit  (original emphasis):
Life exists only so long as it provides for its own continuance. Whatever men live for, today most live only because of the market order. We have become civilized by the increase of our numbers just as civilization made that increase possible: we can be few and savage, or many and civilized. If reduced to its population of ten thousand years ago, mankind could not preserve civilization. Indeed, even if knowledge already gained were preserved in libraries, men could make little use of it without numbers sufficient to fill the jobs demanded for extensive specialisation and division of labour.