How do I add the time dimension in a XY scatter or bubble plot?

Dear all,

I am trying to plot the combination of "b" and "c" series as a time trend.... Using the option of XY scatter or bubble plot, I assign the x and y values in each point. But I can never get them in time sequence because they end up appearing according to the values. I tried to activate the secondary x axis option, but it is not somehow available. Any ideas please?? Im using Excel 2007. Thanking you in advance...

Time b c
2008 278,08 341,96
2009 271,26 331,43
2010 278,89 343,85
2011 302,17 357,87
2012 305,11 305,98
2013 311,39 307,36
2014 319,71 309,94
2015 329,31 314,49
2016 339,69 315,49
2017 350,56 317,05