You need these two added in code:
setFontSizeAbsolute(getReferenceLineTextY1(0),true);
setFontSizeInPoints(getReferenceLineTextY1(0),20);
ENGINE INT CACHE SET ON
SET PAGE-NUM=NOLEAD
-DEFAULTH &WF_HTMLENCODE=OFF;
SET HTMLENCODE=&WF_HTMLENCODE
SET ARGRAPHENGINE=JSCHART
-DEFAULTH &WF_EMPTYREPORT=ON;
SET EMPTYREPORT=&WF_EMPTYREPORT
SET EMBEDHEADING=ON
SET GRAPHDEFAULT=OFF
-DEFAULTH &WF_STYLE_UNITS='PIXELS';
-DEFAULTH &WF_STYLE_HEIGHT='405.0';
-DEFAULTH &WF_STYLE_WIDTH='770.0';
-DEFAULTH &WF_TITLE='WebFOCUS Report';
GRAPH FILE CAR
-* Created by Info Assist for Graph
SUM CAR.BODY.RETAIL_COST
BY CAR.ORIGIN.COUNTRY
ON GRAPH PCHOLD FORMAT JSCHART
ON GRAPH SET VZERO OFF
ON GRAPH SET UNITS &WF_STYLE_UNITS
ON GRAPH SET HAXIS &WF_STYLE_WIDTH
ON GRAPH SET VAXIS &WF_STYLE_HEIGHT
ON GRAPH SET LOOKGRAPH BAR
ON GRAPH SET AUTOFIT ON
ON GRAPH SET STYLE *
*GRAPH_SCRIPT
setPieDepth(0);
setPieTilt(0);
setDepthRadius(0);
setCurveFitEquationDisplay(false);
setPlace(true);
*END
INCLUDE=IBFS:/FILE/IBI_HTML_DIR/ibi_themes/Warm.sty,$
TYPE=REPORT, TITLETEXT=&WF_TITLE.QUOTEDSTRING, ORIENTATION=LANDSCAPE, $
TYPE=DATA, COLUMN=N1, BUCKET=x-axis, $
TYPE=DATA, COLUMN=N2, BUCKET=y-axis, $
COLUMN=N2, ITEM=1, GRAPH-COMMAND='setReferenceLineValue(getReferenceLineY1(0),$VALUE)', $
*GRAPH_SCRIPT
setReportParsingErrors(false);
setSelectionEnableMove(false);
setReferenceTextPosition(getReferenceLineTextY1(0),1);
setDisplay(getReferenceLineY1(0),true);
setBorderColor(getReferenceLineY1(0),new Color(0,0,0));
setFillColor(getReferenceLineTextY1(0),new Color(0,0,0));
setLineWidth(getReferenceLineY1(0),3);
setLineBasicStrokeType(getReferenceLineY1(0),13);
setTextString(getReferenceLineTextY1(0),"Retail Cost");
setDisplay(getReferenceLineTextY1(0),true);
setFontSizeAbsolute(getReferenceLineTextY1(0),true);
setFontSizeInPoints(getReferenceLineTextY1(0),20);
*END
ENDSTYLE
END
-RUN
WebFOCUS 8206, Unix, Windows