Values returning as NaN after nesting

I'm having trouble nesting my data. I get my count as NaN when i do the following:

  var sumstat = d3.nest()
.key(function(d) {; return d.region;})
.key(function(d) {return +d.year})
.rollup(function(d) {return d.count;})
.entries(data);

This is the output I get on my console:

I'm not sure how I can capture the count. Any help please?