@hbdchick would you happen to have historical data on cousin marriage in Scandinavia and/or GB (esp Scotland)?
@tebrmc some data for sweden here: https://hbdchick.wordpress.com/2011/09/18/inbreeding-in-18th-and-19th-century-sweden/ … & more vague info here: https://hbdchick.wordpress.com/2011/09/17/inbreeding-in-sweden/ … & here: https://hbdchick.wordpress.com/2014/12/14/mating-patterns-in-medieval-norway/ …