On the following graph, use the green point $($triangle symbol$)$ to plot the annual total revenue when the market price is $$10,$ $$15,$ $$20,$ $$25,$ $$30,$ $$35,$ and $$40$ per bippitybop. According to the midpoint method, the price elasticity of demand between points A and B on the initial graph is approximately $.$

Suppose the price of bippitybops is currently $$15$ per bippitybop, shown as point B on the initial graph. Because the price elasticity of demand between points A and B is $\_\_\_\_,$ a $$5-$per$-$bippitybop increase in price will lead to $\_\_\_\_\_\_\_$ in total revenue per day.

In general, in order for a price decrease to cause a decrease in total revenue, demand must be $\_\_\_\_\_\_$