Locale-aware number format for the tick values in the Y axis. Overrides numberFormat for this axis; an explicit yAxisTickFormat takes precedence over it. It could be a preset name (comma, percent, dollar, euro, pound, yen, compact), a sprintf format string, or an object, i.e. {"locale": "en-US", "style": "decimal|percent|currency|compact", "currency": "USD", "decimals": 1, "grouping": true, "prefix": "", "suffix": ""}
string or object