Superscript negative exponent lable on axis in SAS Proc SGPLOT - unicode

Question

Can anyone help me properly add a superscript -1 to the x-axis? The code below is what I have tried based on other searches. However, the resulting graph has a box where the negative sign should be. Anyone have any ideas as to why that may be happening? Thank you in advance.
ods escapechar='~';
proc sgplot data=fig2;
series x=hour y=SB /legendlabel='SB' MARKERS LINEATTRS = (THICKNESS = 1 pattern=solid) MARKERATTRS=(SYMBOL=DIAMOND);
series x=hour y=LPA /legendlabel='LPA' MARKERS LINEATTRS = (THICKNESS = 1 pattern=solid) MARKERATTRS=(SYMBOL=PLUS);
series x=hour y=MPA /legendlabel='MPA' MARKERS LINEATTRS = (THICKNESS = 1 pattern=solid) MARKERATTRS=(SYMBOL=CIRCLE);
series x=hour y=MVPA /legendlabel='MVPA' MARKERS LINEATTRS = (THICKNESS = 1 pattern=solid) MARKERATTRS=(SYMBOL=TRIANGLE);
series x=hour y=VPA /legendlabel='VPA' MARKERS LINEATTRS = (THICKNESS = 1 pattern=solid) MARKERATTRS=(SYMBOL=SQUARE);
yaxis label= "Absolute Percent Error (%)" ;
**xaxis label= "Wear Time hours·day ~{unicode'207b'x}~{unicode'00b9'x}"** type=discrete ;
keylegend /position=right NOBORDER;
run;

Answer 1

Most likely this is because the font in your template does not support Unicode characters. You need to modify the template.
See this for an example of Unicode with PROC SGRENDER http://support.sas.com/kb/49/694.html
So to fit your example, first define the new style:
proc template;
define style unifonts;
parent=Styles.meadow;
style Graphfonts from GraphFonts /
'GraphValueFont' = ("Monotype Sans WT J",12pt)
'GraphLabelFont' = ("Monotype Sans WT J",12pt)
'GraphDataFont' = ("Monotype Sans WT J",12pt)
'GraphTitleFont' = ("Monotype Sans WT J",12pt)
'GraphFootnoteFont'=("Monotype Sans WT J",12pt)
'GraphAnnoFont'=("Monotype Sans WT J",12pt);
end;
run;
Then use that style and run your graph
ods html style=unifonts ;
<your code here>
See also the documentation that walks you through altering graph styles http://support.sas.com/documentation/cdl/en/grstatug/67914/HTML/default/viewer.htm#n1sj0165otoa5cn1jr451nhq0sjc.htm