The TIOBE company has an own list of programming language popularity where you can check programming language popularity.

This list is not even near 100% accurate but gives you a very good hint of which language to use and more likely which language to NOT use when developing an advanced software. The index itself is built upon a not so sophisticated method, which is basically to search the major search engines with this term:
+”<language> programming”
and count the number of hits received.

That’s why the list is not that accurate but it still gives you a rough estimate of which languages that are growing and which are not.

The top 20 popular programming languages in September 2007 is (the % is of total market share):

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

Java		21.701%
C		14.908%
Visual Basic	10.748%
PHP		10.204% 
C++		9.938%
Perl		5.416%
C#		3.583%
Python		3.025%
Javascript	2.722%	
Ruby		2.065%
PL/SQL		1.860%
SAS		1.395%
D		1.370%
Delphi		1.224%
ABAP		0.706%
Lisp/Scheme	0.633% 	
COBOL		0.630% 
Lua		0.572%
Ada		0.566%
Fortran		0.478%

To notice from the source both c++ and c is falling in line, although it’s not much. You can also note that PHP is actually more popular then C++. This could be because of PHP’s simplicity compared to C++ which generate more “newbie-questions” about PHP rather then C++.

The top climber, Lua, is not a very known programming language. Lua is most known for homebrewed software for Playstation Portable and Nintendo DS. On a later matter, the language has been used to create scripts in World of Warcraft, which most likely is the reason for the huge climbing (thanks Sickwookie comment #1). The language itself is claimed to be a mix of Python, Icon, Scheme and Lips.
The list from 21-50 can is here (the % is of total market share):

21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

Transact-SQL 	0.452%
Pascal 		0.429%
ActionScript 	0.407%
FoxPro/xBase 	0.387%
Awk 		0.383%
MATLAB 		0.364%
IDL 		0.326%
Prolog	 	0.313%
ColdFusion 	0.297%
Logo 		0.249%
Bash 		0.221%
RPG 		0.198%
Tcl/Tk 		0.187%
LabView 	0.178%
Haskell 	0.147%
Smalltalk 	0.145%
CL (OS/400) 	0.133%
Forth 		0.119%
Natural 	0.116%
Erlang 		0.109%
VBScript 	0.102%
APL 		0.101%
REXX 		0.088%
Objective-C 	0.084%
OCaml 		0.082%
Icon 		0.079%
Postscript 	0.076%
Lingo 		0.075%
ML 		0.074%
R		0.072%