The <ChartHeader> is a component which combines the chart title and year. It is shown above the chart.
Both title and year are optional. When neither is provided then the component renders no DOM element.
In many cases the <ChartHeader> will display both the title and year, or just the year.
The <ChartHeader> above multi-line charts (time series) will include only the title and no year.
Note: The <ChartHeader> component includes bottom margin!