Step 1: From the graph, sales of X in 2018 = 40020 kg and sales of Y in 2018 = 75070 kg. Total sales in 2018 = 40020 + 75070 = 115090 kg.
Step 2: Required percentage = \( \dfrac{40020}{115090} \times 100 \).
Step 3: This gives \( 34.77\% \), which matches option 4.