Hi All, I have annual data on the sales revenue of firms. I have the year variable as follows: year = 2008, 2009, 2010, 2015, 2016, 2017. I want to take lead of the sales variable by using the command sales[_n+1]. The problem is the gap in my yearly data, i.e., between 2010 and 2015. Can you please help me with how can I take lead of my sales variable in this data set? I would appreciate your reply.