1 represents 100%. To find how much represent 2.8%, we can apply the next proportion:
[tex]\frac{100\text{ \%}}{2.8\text{ \%}}=\frac{1}{x}[/tex]Solving for x:
[tex]\begin{gathered} 100\cdot x=1\cdot2.8 \\ x=\frac{2.8}{100} \\ x\approx0.03 \end{gathered}[/tex]0.03 is 2.8% of 1.