d3.js & nvd3.js axis and label precision formatting
===

Using the stacked area chart as seen in this example
http://nvd3.com/ghpages/stackedArea.html

Trying to format the y-axis tick labels and the tooltip labels to be integers instead of floats. Tried changing the follow code from

    chart.yAxis
            .axisLabel('Users')
            .tickFormat(d3.format(',.2f'));

to

    chart.yAxis
            .axisLabel('Users')
            .tickFormat(d3.format(',.0d'));

Precision remains unchanged (still shows values to the hundredths place). I've followed the Github Wiki to no avail https://github.com/mbostock/d3/wiki/Formatting#wiki-d3_format

Any suggestions or hints will be greatly appreciated.