The conventional launch sites could theoretically launch about 15 V-1s per day, but this rate was difficult to achieve on a consistent basis; the maximum rate achieved was 18. Overall, only about 25% of the V-1s hit their targets, the majority being lost because of a combination of defensive measures, mechanical unreliability or guidance errors. With the capture or destruction of the launch facilities used to attack England, the V-1s were employed in attacks against strategic points in Belgium, primarily the port of Antwerp.