The mortgage burden

I was reading Bernanke & Gertler's (1995) classic, "Inside the Black Box: The Credit Channel of Monetary Policy Transmission" and was interested in their treatment of the "mortgage burden". Following Boldin (1994) they define it thus: "the ratio of mortgage payments to income for the median new home buyer." I've tried to track down the Boldin article to see this in more detail, but can't find a link

Anyway, I wondered what it would look like for the UK in the lead up to the global financial crisis and asked on Twitter. Neal Hudson kindly shared this chart: