Why is my Rust version of "wc" slower than the one from GNU coreutils?

Consider this program:

use std::io::BufRead;
use std::io;

fn main() {
    let mut n = 0;
    let stdin = io::stdin();
    for _ in stdin.lock().lines() {
        n += 1;
    }
    println!("{}", n);
}

Why is it over 10x as slow as the GNU version of wc? Take a look at how I measure it:

$ yes | dd count=1000000 | wc -l
256000000
1000000+0 records in
1000000+0 records out
512000000 bytes (512 MB, 488 MiB) copied, 1.16586 s, 439 MB/s
$ yes | dd count=1000000 | ./target/release/wc
1000000+0 records in
1000000+0 records out
512000000 bytes (512 MB, 488 MiB) copied, 41.685 s, 12.3 MB/s
256000000