Canada's non-resource exports have "faltered" of late and remain "a puzzle that merits further study," according to central bank Governor Stephen Poloz. One thing is clear, however: Canada's share of U.S. goods imports has eroded over the past four decades. "Notably, the U.S. now imports roughly equal dollar amounts of goods from Mexico and Canada, versus 10 years ago when they brought in $1.70 (U.S.) from Canada for every $1 from Mexico," Robert Kavcic, senior economist at BMO Nesbitt Burns, said in a note.