Histogram: increasing space between bars

How can I maintain the same width of the bars, and at the same time increasing the space that separates them?

documentclass{article}
usepackage{pgfplots}
usepackage{tikz}

begin{document}

    begin{figure}[p]
    centering  
    begin{tikzpicture}[font=footnotesize]
        begin{axis} [ylabel={Results},
            width=textwidth,
            height=8cm,
            enlarge x limits=0.03,
            ybar,ymin=0,ymax=1750,xtick=data,
            ymajorgrids=true,xtick pos=left,
            ytick={0, 500, 1000, 1500},
            yticklabels={$0$,$500$,$1000$,$1500$},
            x tick label style=%
            {rotate=90,anchor=east},
            xticklabel interval boundaries,
            symbolic x coords={$1990$,$1991$,$1992$,$1993$,$1994$,$1995$,$1996$,$1997$,$1998$,$1999$,$2000$,$2001$,$2002$,$2003$,$2004$,$2005$,$2006$,$2007$,$2008$,$2009$,$2010$,$2011$,$2012$,$2013$,$2014$,$2015$,$2016$,$2017$,$2018$,$2019$,$2020$},
            ]
            addplot
            [ybar interval, fill=cyan,
            draw=black] coordinates
            {($1990$, 31) ($1991$, 23) ($1992$, 36) ($1993$, 34) ($1994$, 46) ($1995$, 72) ($1996$, 127) ($1997$, 105) ($1998$, 137) ($1999$, 147) ($2000$, 135) ($2001$, 162) ($2002$, 211) ($2003$, 209) ($2004$, 301) ($2005$, 349) ($2006$, 452) ($2007$, 474) ($2008$, 635) ($2009$, 943) ($2010$, 998) ($2011$, 1047) ($2012$, 1069) ($2013$, 1173) ($2014$, 1236) ($2015$, 1106) ($2016$, 1236) ($2017$, 1329) ($2018$, 1447) ($2019$, 1697) ($2020$, 1291)
            };          
        end{axis}
    end{tikzpicture}
end{figure}

end{document}

I tried to add the bar width=9pt, and to eliminate ybar interval, but the space between bars seems to be different for some pairs of bars.