Try changing your Y-axis modeling type to Continuous (currently you have Nominal). You can change it directly from graph builder by right-clicking on the bars on column selection or you could change them from data table by right clicking on column header.
jthi_0-1689009195491.png
Nominal:
jthi_1-1689009240108.png
Continuous:
jthi_2-1689009248324.png
-Jarmo