It's interesting that your electricity use graph peaks in March/April. The comparison graphs peak in December/January; this is probably because they include homes that have heat pumps and judging from your natural gas use you have a furnace. That explains why you have an absence of a peak in Jan, but the peak in March is mystifying. Air conditioning use should be highest in July or August. You should think about your air conditioning and heating systems. A/C units slowly get less efficient as they get older and get much less efficient when the refrigerant charge is not right. If you get a new furnace, you have a number of efficiency options: 2-stage heating, an ECM (aka variable speed) blower motor, or a 90% or even 96% efficiency system.