geom_histogram从图中丢失数据

Question

我有数据：

> dat
 slopes     sig
1  -1.24285       insignificant
2   0.01733       insignificant
3  -0.00050       insignificant
4  -0.06455       insignificant
5   0.00608       insignificant
6   0.01669       insignificant
7  -0.00751       insignificant
8  -0.00987 p <0.05
9  -0.00069       insignificant
10  0.00482       insignificant
11 -0.00446       insignificant
12 -0.00035       insignificant
13 -0.00205       insignificant
14  0.00585       insignificant
15  0.00507       insignificant
16  0.00002       insignificant
17 -0.00279       insignificant
18 -0.00580 p <0.05
19  0.00399       insignificant
20 -0.00647 p <0.05
21 -0.00268       insignificant
22 -0.00696       insignificant
23 -0.00678       insignificant
24  0.00034       insignificant
25 -0.00208       insignificant
26 -0.00012       insignificant
27 -0.00027       insignificant
28  0.00082       insignificant
29  0.01113       insignificant
30 -0.00171       insignificant
31  0.00134       insignificant
32 -0.14532       insignificant
33 -0.00433       insignificant
34  0.00440       insignificant
35  0.00369       insignificant
36 -0.00063       insignificant
37  0.01138       insignificant
38  0.00323       insignificant
39 -0.03902 p <0.05

我试图使用以下代码在ggplot2中绘制堆积直方图：

 ggplot(dat,aes(x=slopes,fill=sig))+
  labs(title='Log(Biomass+1)') +

  geom_histogram(data=dat,position='stack',aes(x=slopes),color='black',binwidth=diff(range(dat$slopes))/20)+   # without change.
      scale_fill_manual(values=c('darkgray','pink'),name='Significance') +
      labs(x='Slope', y='Frequency', size=20) +
      theme(axis.text = element_text(size = rel(1.5)),
            axis.title = element_text(size = rel(1.25)),
            plot.title = element_text(size = rel(2))) + 
  scale_y_continuous(expand=c(0,0), limits=c(0,10))+
      theme_bw()

但并非所有数据都被绘制。事实上，我的结果是：

如何让直方图显示所有数据？