A seasonal index of $1\mathrm{.}3$ for the month of January indicates which of the following?

Jinuary has $30\%$ iess sales than the average.

Sales for January are $1,3$ units above the seisonal average.

January sales are $1\mathrm{.}3$ units below the average.

$30\%$ more sales are expected in January when compared to the seasonal average.