A concentrated vertical load of $3000$ $\text{kN}$ is applied on a horizontal ground surface. Points $P$ and $Q$ are at depths $1 \:m$ and $2\: m$ below the ground, respectively, along the line of application of the load. Considering the ground to be a linearly elastic, isotropic, semi-infinite medium, the ratio of the increase in vertical stress at $P$ to the increase in vertical stress at $Q$ is _______________. (in integer)