This is great info, UltArc! Thanks for taking the time to put it together.
I'll admit I'm surprised at how much the Micra leads, considering its fuel consumption is higher than the Spark & quite a bit higher than Mirage. There's obviously something to be said for lowest purchase price.
I may put together a Canadian version of this comparison using stats from north of the border -- it will change the outcome somewhat because we have slightly different MSRP's, and our fuel prices are quite a bit higher than yours (which will reduce the time a cheaper to buy but thirstier vehicle will hold the lead position).
View my fuel log 2015 Micra S manual: 5.0 L/100 km ... 56.5 mpg (Imp) ... 20.0 km/L ... 47.0 mpg (US) ...