Hmmm.

Louis St-Laurent, John Diefenbaker, Lester Pearson, Pierre Elliott Trudeau, Joe Clark, Pierre Elliott Trudeau redux, John Turner, Brian Mulroney, Kim Campbell, Jean Chretien, Paul Martin, Stephen Harper, Justin Trudeau.

So, thirteen prime-ministerial tenures.

Of those, PE Trudeau was the third-longest serving PM since Confederation, with 15 years and 165 days in office; Jean Chretien was the fifth longest serving, with 10 years and 38 days in office; Stephen Harper was the sixth-longest serving, with 9 years and 271 days in office; and Brian Mulroney was the seventh-longest serving, with 8 years and 281 days in office.

Each of the Stephen Harper years felt like three. Sometimes four.