A dealer gets refrigerators from 3 different manufacturing companies $C_1, C_2$ and $C_3 .25 \%$ of his stock is from $C_1, 35 \%$ from $C_2$ and $40 \%$ from $C_3$. The percentages of receiving defective refrigerators from $C_1, C_2$ and $C_3$ are $3 \% 2 \%, 1 \%$ respectively. If a refrigerator sold at random is found to be defective by a customer, then the probability that it is from $\mathrm{C}_2$ is