I've looked at the 2003/04, 2006/07, 2009/10, 2010/11, 2011/12, 2012/13, 2017/18 seasons along with this season.

Goals scored by strikers as a percentage of all goals:

2003/04: 63.0%
2006/07: 51.8%
2009/10: 45.5%
2010/11: 58.0%
2011/12: 41.0%
2012/13: 40.5%
2017/18: 21.1%
2019/20: 32.9%

2003/04 was the season of Thorne and Earnshaw. Earnie hit 26 in all competitions that season. Andy Campbell helped out with a few. 2006/07 was Chopra's best season for us. The three Dave Jones seasons shows a similar reliance on strikers to provide goals - the 2009/10 season figure is lower due to City legend Peter Whittingham (RIP) scoring 25 goals. Malky Mackay's City had less reliance on strikers to score goals and, erm, the figure of Warnock's promoted side is quite extraordinary.

Goals scored by midfielders as a percentage of all goals:

2003/04: 28.8%
2006/07: 35.7%
2009/10: 47.7%
2010/11: 32.1%
2011/12: 43.6%
2012/13: 39.2%
2017/18: 59.2%
2019/20: 54.8%

Goals scored by defenders as a percentage of all goals:

2003/04: 8.2%
2006/07: 12.5%
2009/10: 6.8%
2010/11: 9.9%
2011/12: 15.4%
2012/13: 20.3%
2017/18: 19.7%
2019/20: 12.3%

It should be noted that few teams play with 2 strikers any more. One striker, 2 wingers and 3 in the middle is the usual formation nowadays. If you take wide midfielders as attackers instead of midfielders for the 2017/18 and 2019/20 season, you get different results (obviously). Wingers a decade ago were mainly to provide crosses. Their role has changed somewhat and they are also there to provide support to the loan striker.

In 2017/18 our wide midfielders contributed 23 goals. This season it is 17. Chris Burke, arguably our best winger from the Jones' era had an entirely different role, though scored 15 between the 2 seasons mentioned.

If you count our wide midfielders as attackers, not midfielders, this season has seen the second highest percentage of goals scored by attackers since that 2003/04 season with Lennie Lawrence in charge.